System option modes for VSP 5000 series

System Administrator Guide for VSP 5000 Series

Version
90-09-2x
Audience
anonymous
Part Number
MK-98RD9009-16

To provide greater flexibility, the storage systems have additional operational parameters called system option modes (SOMs) that allow you to tailor the storage system to your unique operating requirements. The SOMs are set on your storage system by your service representative.

The following table lists and describes the SOMs for VSP 5000 series. Review the SOMs for your storage system, and work with your service representative to ensure that the appropriate SOMs for your operational environment are configured on your storage system.

Note: The SOM information might have changed since this document was published. For the latest SOM information, contact customer support.
Mode Category Description MCU/RCU
15 Common

This SOM can reduce the host response time to be within about 6 seconds.

Mode 15 = ON (default):
  • Upper limit for retry of drive is reduced from 2 sec. to 0.5 sec.
  • If a drive failure occurs in read processing, a correction read processing is executed immediately.
  • I/O watching time is changed from 6.5 sec. to 4.5 sec. (I/O watching time including DMA transfer is 10 sec.)
  • Read or write processing is not retried for time-out failure.
Mode 15 = OFF:
  • Upper limit for retry of drive is 2 sec.
  • If a drive failure occurs in read processing, a retry processing corresponding to the type of failure is executed.
  • I/O watching time is 6.5 sec. (I/O watching time including DMA transfer is 10 sec.)
  • Read or write processing is retried for time-out failure.
Notes:
  1. This SOM applies at a site where a drive response delay may affect business operations.
  2. When Dynamic Sparing or Auto Correction Mode is used, because host I/Os conflict with copy processing, the I/O watching time is 30 seconds even when this SOM is set to ON.
  3. Even though SOM 15 is set to ON, the function does not apply to SATA or NL-SAS drives.
  4. When SOM 771 or SOM 797 is set to ON, the setting of SOM 771/797 is prioritized for the read I/O watching time.
  5. For additional details about this SOM (interaction with other SOMs, operational details), contact customer support (see SOM015 sheet).
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20

TrueCopy for Mainframe

Universal Replicator for Mainframe

S-VOL read only function (secondary system only).

Mode 20 = ON: The S-VOL accepts host read operations while the pair is split.

Mode 20 = OFF (default): The S-VOL does not accept host read operations while the pair is split.

RCU
22 Common Regarding the correction copy or the drive copy, in case ECCs/LRC PINs are set on the track of copy source HDD, SOM 22 can be used to interrupt the copy processing (default) or to create ECCs/LRC PINs on the track of copy target HDD to continue the processing.

Mode 22 = ON: If ECCs/LRC PINs (up to 64) have been set on the track of copy source HDD, ECCs/LRC PINs (up to 64) will be created on the track of copy target HDD so that the copy processing will continue. If the number of ECCs/LRC PINs exceeds 64, the corresponding copy processing will be interrupted.

Mode 22 = OFF (default): If ECCs/LRC PINs have been set on the track of copy source HDD, the copy processing will be interrupted. (First recover ECCs/LRC PINs by using the PIN recovery flow, and then perform the correction copy or the drive copy again).

One of the controlling option for correction/drive copy.

None
36 TrueCopy for Mainframe Selects function of CRIT=Y(ALL) or CRIT=Y(PATHS).

Mode 36 = ON: CRIT=Y(ALL) => equivalent to Primary Volume Fence Level = Data.

Mode 36 = OFF (default): CRIT=Y(PATHS) => equivalent to Primary Volume Fence Level = Status.

MCU
64 TrueCopy for Mainframe Mode 64 = ON:
  • When receiving the Freeze command, pair volumes in the storage system that fulfill the conditions below are suspended and the status change pending (SCP) that holds write I/Os from the host is set. The path between MCU and RCU is not deleted. Query is displayed only but unusable.
  • When receiving the RUN command, the SCP status of the pairs that fulfill the conditions below is released.
  • When a Failure Suspend occurs while Freeze Option Enable is set, except the pair in which the Failure Suspend occurs, other pairs that fulfill the conditions below go into SCP state.
Conditions:
  • TCz P-VOL
  • Mainframe volume
  • Pair status: Duplex/Pending
Mode 64 = OFF (default):
  • When receiving the Freeze command, pairs that fulfill the conditions below are suspended and the SCP is set. In the case of CU emulation type 2105/2017, the path between MCU and RCU is deleted, while the path is not deleted but unusable with Query displayed only in the case of CU emulation type 3990.
  • When receiving the RUN command, the SCP status of the pairs that fulfill the conditions below is released.
  • When a Failure Suspend occurs while the Freeze Option Enable is set, except the pair in which the Failure Suspend occurs, other pairs that fulfill the conditions below go into SCP state.
Conditions:
  • TCz P-VOL
  • Mainframe volume
  • Pair status: Duplex/Pending
  • A pair whose RCU# is identical to the RCU for which the Freeze command is specified.
Notes:
  1. General use: SOM 64 = OFF (default).
  2. When all the following conditions are met, set SOM 64 to ON:
    • Customer requests to stop the update I/O operation to the RCU of a TCz pair for the whole storage system.
    • Disaster Recovery function such as GDPS, HyperSwap, or Fail Over/ Fail Back, which requires compatibility with IBM® storage, is not used as SOM 64 operates without having compatibility with IBM® storage.
    • Only Peer-to-Peer-Remote-Copy operation. (Do not use it in combination with Business Continuity Manager.)
  3. Even though the Failover command is not an applicable criterion, when executing the Failover command while SOM 114 is ON, since ports are not automatically switched, the Failover command fails.
  4. With increase of Sync pairs in storage system, the time period to report the completion of Freeze command and RUN command gets longer (estimate of time to report completion: 1 second per 1000 pairs), and MIH may occur.
Both
104 TrueCopy for Mainframe Changes the default of the CGROUP Freeze option. Mode 104 = OFF is the default setting. MCU
114 TrueCopy for Mainframe

Universal Replicator for Mainframe

This SOM enables or disables LCP/RCP port to be automatically switched over when PPRC command ESTPATH/DELPATH is performed.

Mode 114 = ON: Automatic port switching during ESTPATH/DELPATH is enabled.

Mode 114 = OFF (default): Automatic port switching during ESTPATH/DELPATH is disabled.

Notes:
  1. If an incorrect port is selected while this SOM is set to ON, and if ESTPATH is executed when no logic path exists, the port is switched to RCP.
  2. If TPC-R (IBM® software for disaster recovery), set this SOM to OFF.
  3. For Fibre Channel interface, do not use the CESTPATH and CDELPATH commands at the same time as the SCSI path definition function. Fibre Channel interface ports need to be configured as initiator ports or RCU target ports before the CESTPATH and CDELPATH commands are issued.
MCU
142 Common This SOM is used to prevent storage systems from going down by blocking a failure drive at an early point when time-out occurs frequently for commands issued to the drive.

When a command issued to a drive times out, the failure is counted on the failure counter of the drive port. If the failure counter reaches the port blockage threshold, the drive port is blocked. By setting this SOM to ON, the port is blocked when the number of failures reaches half of the threshold, which mitigates the occurrence possibility of the host time-out.

Mode 142 = ON (default): The threshold value of blocking a drive port due to command time-out is changed to half of the normal threshold.

Mode 142 = OFF: The threshold value of blocking a drive port due to command time-out does not change.

Notes:
  1. This SOM should always be set to ON. This SOM can be set to OFF only when the customer does not allow to set this SOM to ON for a storage system already in production.
  2. Settings of SOM 363, SOM 365, and SOM 809 are related each other. The order of priority for the setting to be enabled is SOM 809, SOM 363, SOM 365, and then SOM 142. For details, contact customer support (see the mode document of each SOM).
  3. This SOM is effective for the entire storage system.
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164 Common This SOM is used to select whether to suppress performing the write-through operation for writes from a host if CM/SM one-side blockage occurs. The write-through operation directly writes data to a drive to secure data, which reduces I/O response compared to cache writes. By enabling SOM 164 (which suppresses the write-through operation), I/O response is not reduced and performance is maintained.

Mode 164 = ON: When CM/SM is blocked or in transition to blockade status, the write-through operation and I/O multiple-operation prevention are not performed. However, the write through operation and I/O multiple-operation prevention during power supply failure mode commanded from HP-UX are performed.

Mode 164 = OFF (default): Write-through-operation and IO-multiple-operation prevention are performed when CM/SM is blocked or in transition to blockade status.

Notes:
  1. Data is not secured at the failure on both sides of CM/SM. Recovery from all volume backups is required.
  2. Determine whether to set the mode to ON or OFF on the following basis:

    OFF: The mode is set to OFF to secure the data even when a CM/SM dual failure occurs. As the write through works for data assurance at CM/SM one-side blockage, make sure to design a system where performance degradation such as I/O response is acceptable in a configuration where data from host is duplicated on primary and secondary storage systems.

    ON: The mode is set to ON to prioritize maintaining the performance over data assurance as a single storage system when a CM/SM dual failure occurs. When the mode is set to ON, the data may be lost at the CM/SM dual failure. If high data reliability is required for the storage system like RAID, data duplication should be realized by the entire system like a configuration where data from host is duplicated on primary and secondary storage systems.

    Caution: If you set SOM 164 to ON for GAD, volumes that are being used by functions other than GAD and volumes in the SMPL status behave the same as GAD volumes. Before you set SOM 164 to ON, check the effects on other functions.

  3. Using this SOM poses a risk of losing the data at a CM/SM dual failure. If high data reliability is required for the storage system like RAID, data duplication should be realized by the entire system like the configuration in which data from host is duplicated on primary and secondary storage systems.
  4. When this SOM is used, the time required for blocking CM/SM at maintenance is longer than that when this SOM is set to OFF so that the maintenance operation may end abnormally if the amount of write pending is large. Therefore, perform the maintenance operation when the amount of write pending is as less as possible. If the maintenance operation ends abnormally, replace the blocked part to recover.
  5. When setting the function to each LDEV is desired, contact customer support. (See "WR Through" function on the System Option window. See 2.13 System option in the SVP section of Maintenance Manual. Also, follow the above (1) even when the "WR Through" is used.)
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190 TrueCopy for Mainframe Allows you to update the VOLSER and VTOC of the S-VOL while the pair is suspended if both SOM 20 and SOM 190 are ON.

Mode 190 = ON: When SOM 20 (S-VOL read-only option) and this SOM are both ON, you can update the VOLSER and VTOC of the S-VOL while the pair is suspended. When the pair is resumed, the VOLSER and VTOC of the S-VOL are overwritten with the VOLSER and VTOC of the P-VOL.

Mode 190 = OFF (default): Even when SOM 20 (S-VOL read-only option) is ON, you cannot update the VOLSER or VTOC of the S-VOL while the pair is suspended.

Notes:
  1. This SOM is applied along with SOM 20 when data writing to a VTOC area in the S-VOL of a suspended TCz pair is required.
  2. If a write I/O is issued wrongly to an S-VOL VTOC area of a suspended TCz pair, the consistency between the P-VOL and the S-VOL is lost, but the inconsistency is solved by a resume operation.
Both
305 Mainframe This SOM enables the pre-label function (creation of VTOC including VOLSER).

Mode 305 = ON: Pre-label function is enabled.

Mode 305 = OFF (default): Pre-label function is disabled.

Notes:
  1. Set SOM 305 to ON before performing LDEV Format for a mainframe volume if you want to perform OS IPL (volume online) without fully initializing the volume after the LDEV Format. However, full initialization is required in actual operation.
  2. Processing time of LDEV format increases by as much as full initialization takes.
  3. The following functions and conditions are not supported:
    • Quick format
    • 3390-A (Dynamic Provisioning attribute)
    • Volume Shredder
  4. Full initialization is required in actual operation.
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308 TrueCopy for Mainframe

Universal Replicator for Mainframe

Allows you to specify whether the Remote Copy Path status, SIM218x, is reported to the host.

SIM RC=2180 (RIO path failure between MCU and RCU) is not reported to host. The storage system reports SSB with F/M=F5 instead of reporting SIM RC=2180 in the case. Micro-program has been modified to report SIM RC=2180 with newly assigned SOM as individual function for specific customer.

Mode 308 = ON: SIM RC 2180 is reported, which is compatible with older Hitachi specification.

Mode 308 = OFF (default): Reporting is compatible with IBM - Sense Status report of F5.

MCU
310 Common

Mode 310 = ON: The monitoring timer for MP hang-up is 6 seconds and returning a response to the host within 8 seconds is guaranteed.

Mode 310 = OFF (default): The monitoring timer for MP hang-up remains 8 seconds.

Notes:
  1. This SOM applies to a site where strict host response performance is required.
  2. If a hardware failure occurs when this SOM is set to ON, the time until MPB blockage that is determined is shorter than usual.
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454 Virtual Partition Manager CLPR (function of Virtual Partition Manager) partitions the cache memory in the storage system into multiple virtual cache and assigns the partitioned virtual cache for each use. If a large amount of cache is required for a specific use, it can minimize the impact on other uses. The CLPR function works as follows depending on whether SOM 454 is set to ON or OFF.

Mode 454 = OFF (default): The amount of the entire destage processing is periodically determined by using the highest workload of all CLPRs (*a). (The larger the workload is, the larger the amount of the entire destage processing becomes.)

*a: (Write Pending capacity of CLPR#x of concerned MPB) ÷ (Cache capacity of CLPR#x of concerned MPB), x=0 to 31

CLPR whose value above is the highest of all CLPRs

Because the destage processing would be accelerated depending on CLPR with high workload, when the workload in a specific CLPR increases, the risk of host I/O halt would be reduced.

Therefore, set SOM 454 to OFF in most cases.

Mode 454 = ON: The amount of the entire destage processing is periodically determined by using the workload of the entire system (*b). (The larger the workload is, the larger the amount of the entire destage processing becomes.)

*b: (Write Pending capacity of the entire system of concerned MPB) ÷ (Cache capacity of the entire system of concerned MPB)

Caution: Because the destage processing would not be accelerated even if CLPR has high workload, when the workload in a specific CLPR increases, the risk of host I/O halt would be increased. Therefore, set SOM 454 to ON only when a CLPR has constant high workload and the I/O performance in a CLPR with low workload has higher priority than host I/O halt in the CLPR with high workload.

Notes:
  1. When this SOM is set to ON, even if there is an overloaded CLPR (CLPR with large Write Pending capacity), the amount of destage processing would not increase easily. Therefore TOV(MIH) may occur in the overloaded CLPR. Set this SOM to ON only when the overloaded state of a specific CLPR would not affect other CLPRs.

    When the UR function is used, if user volumes and journal volumes are defined in different CLPRs, when the CLPR to which the journal volumes are assigned overflows, the user volumes become inaccessible. Therefore it is recommended to set this SOM to OFF.

  2. Because the destage processing will have a lower priority in the overloaded CLPR, the overloaded state of the overloaded CLPR is not removed, and TOV(MIH) might occur.
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457 Universal Volume Manager (1) High-Speed LDEV Format for External Volumes

The high-speed LDEV format for external volumes is available by SOM 457 to ON. When SOM 457 is ON, if you select an external volume group and perform an LDEV format, any write processing on the external logical units will be skipped. However, if the external LDEV is a mainframe volume, the write processing for mainframe control information only will be performed after the write skip.

(2) Support for Mainframe Control Block Write GUI

Control Block Write of the external LDEVs in Mainframe emulation has been supported by HDvM - SN (GUI) since 90-04-0x.

Notes:

  • If the LDEV is not written with data "0" before performing the function, the LDEV format might fail.
  • After the format processing, make sure to set SOM 457 to OFF.
Both
459 ShadowImage

ShadowImage for Mainframe

By setting this SOM to ON while an external volume is used as an SI/SIz S-VOL, a function to complete de-staging the S-VOL data to the external volume mapped to the S-VOL before the SI/SIz pair status changes to PSUS works.

The pair status changes to PSUS when the de-staging is complete.

When a split operation is performed for an SI/SIz pair, the pair status changes from PAIR to PSUS(SP) or COPY(SP) (status transition period), and then to PSUS.

The function works during the status transition period.

Mode 459 = ON (default): The pair stays in the status transition period and waits for the de-staging to be complete.

Mode 459 = OFF: Immediately after all differential data is copied to cache, the pair status changes to PSUS. The pair does not stay in the status transition period to wait for the de-staging to be complete.

For details of the function, contact customer support (see SOM459 sheet).

Notes:
  1. Apply the mode for users who require that de-staging S-VOL data to an external volume mapped to the S-VOL has been completed when the pair status changes to PSUS.
  2. The function works for the pairs created while the mode is set to ON and does not work for the pairs created while the mode is set to OFF.
  3. Because de-staging takes place after the copy is complete, the time required to change the status from PSUS(SP) or COPY(SP) to PSUS increases.
  4. When both of SOM 459 and SOM 1263 are used, the throughput improvement by setting SOM 1263 to ON cannot be expected.
  5. At a split operation, the time required to change the status to PSUS when the mode is ON gets longer than that when the mode is set tot OFF.
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467 ShadowImage

ShadowImage for Mainframe

Compatible FlashCopy® V2

Compatible FlashCopy® SE

Universal Volume Manager

Volume Migration

For the following features, the current copy processing slows down when the percentage of "dirty" data is 60% or higher, and it stops when the percentage is 75% or higher. Mode 467 is provided to prevent the percentage from exceeding 60%, so that the host performance is not affected.
  • SI
  • SIz
  • FCv2, FCSE
  • UVM
  • Volume Migration

Mode 467 = ON (default): Copy overload prevention. Copy processing stops when the percentage of "dirty" data reaches 60% or higher. When the percentage falls below 60%, copy processing restarts.

Mode 467 = OFF: Normal operation. The copy processing slows down if the dirty percentage is 60% or larger, and it stops if the dirty percentage is 75% or larger.

Caution: This SOM must always be set to ON when using an external volume as the secondary volume of any of the applicable replication products.

Notes:
  1. It takes longer to finish the copy processing because it stops for prioritizing the host I/O performance.
  2. This SOM supports background copy only. The processing to copy the pre-update data to the S-VOL, which occurs when overwriting data to uncopied slots of P-VOL in Split processing or reading or writing data to uncopied slots of S-VOL, is not supported.
  3. Check the write pending rate of each CLPR per MP unit. Even though there is some free cache capacity in the entire system, if the write pending rate of an MP unit to which pairs* belong exceeds the threshold, the copy operation is stopped.

    *Applies to pairs of SI, SIz, FCv2, FCSE, and Volume Migration.

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471 Thin Image Since the SIM-RCs generated when the Thin Image pool usage rate exceeds the threshold value can be resolved by users, these SIM-RCs are not reported to the maintenance personnel. This SOM is used to report these SIM-RCs to maintenance personnel.

The SIM-RCs reported by setting this SOM to ON are: 601xxx (Pool utilization threshold exceeded), 603000 (SM space warning).

Mode 471 = ON: These SIMs are reported to maintenance personnel.

Mode 471 = OFF (default): These SIMs are not reported to maintenance personnel.

Note: Set this SOM to ON when it is required to inform maintenance personnel of these SIM-RCs.

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474 Universal Replicator

Universal Replicator for Mainframe

UR initial copy performance can be improved by issuing a command from CCI/Business Continuity Manager (BCM) to execute a dedicated script consisting of UR initial copy (Nocopy), UR suspend, TC Sync initial copy, TC Sync delete, and UR resync.

Mode 474 = ON: For a suspended UR pair, a TC (Sync) pair can be created with the same P-VOL/S-VOL so that UR initial copy time can be reduced by using the dedicated script.

Mode 474 = OFF (default): For a suspended UR pair, a TC (Sync) pair cannot be created with the same P-VOL/S-VOL. For this, the dedicated script cannot be used.

If the P-VOL and S-VOL are both DP-VOLs, initial copy performance might not improve with SOM 474 set to ON. This is because with DP-VOLs, not all areas in a volume are allocated for UR; therefore not all areas in the P-VOL are copied to the S-VOL. With less than the full amount of data in the P-VOL being copied, the initial copy completes in a shorter time, which might not be improved with SOM 474.

Notes:
  1. Set this SOM for both primary and secondary storage systems.
  2. When this SOM is set to ON:
    • Execute all pair operations from CCI/BCM.
    • Use a dedicated script.
    • Initial copy operation is prioritized over update I/O. Therefore, the processing speed of the update I/O slows down.
  3. If this SOM is set to ON, the processing speed of update I/O slows down by about 15 μs per command, version downgrade is disabled, and Take Over is not available.
  4. If this SOM is not set to ON for both sides, the behavior is as follows:
    • OFF in primary and secondary storage systems: Normal UR initial copy performance.
    • ON in the primary storage system/OFF in the secondary storage system: TC Sync pair creation fails.
    • OFF in the primary storage system/ON in the secondary storage system: The update data is copied to the S-VOL synchronously.
  5. While this SOM is set to ON, make sure not to perform microcode downgrade to an unsupported version.
  6. While this SOM is set to ON, make sure not to perform the Take Over function.
  7. This SOM cannot be applied to a UR pair that is the second mirror in a URxUR multi-target configuration, URxUR cascade configuration, or 3DC multi-target or cascading configuration of three UR sites. If applied, TC pair creation is rejected with SSB=CBED output.
  8. Before setting SOM 474 to ON, make sure that SOM 1091 is set to OFF. If SOM 1091 is set to ON, set it to OFF first, and then set SOM 474 to ON.
Both
484 TrueCopy for Mainframe

ShadowImage for Mainframe

As the specification of QUERY display using the IBM®-compatible PPRC FC path interface (hereinafter called New Spec) is different from the current specification (hereinafter called Previous Spec), this mode enables to display the PPRC path QUERY with the New Spec or Previous Spec.
  • Mode 484 = ON: PPRC path QUERY is displayed with the New Spec. The status of path using the Fibre Channel interface is displayed. WWNN is indicated.
  • Mode 484 = OFF (default): PPRC path QUERY is displayed with the Previous Spec (ESCON® interface). The status of path using an ESCON® interface is displayed. WWNN is invalid.
Notes:
  1. Set this SOM to ON when you want to maintain compatibility with the Previous Spec for PPRC path QUERY display under the environment where IBM host function (such as PPRC and GDPS) is used.
  2. If the display specification is different between MCU and RCU, it may cause malfunction of host.
  3. When IBM® TPC-R or CSM software for disaster recovery is used, set this SOM to ON.
Both
506 Universal Replicator

Universal Replicator for Mainframe

This SOM is used to enable Delta Resync with no host update I/O by copying only differential JNL instead of copying all data.

The UR Delta Resync configuration is required.

Mode 506 = ON (default):
  • Without update I/O: Delta Resync is enabled.
  • With update I/O: Delta Resync is enabled.
Mode 506 = OFF:
  • Without update I/O: Total data copy of Delta Resync is performed.
  • With update I/O: Delta Resync is enabled.

Note: Even when SOM 506 is set to ON, the Delta Resync may fail and only the total data copy of the Delta Resync function is allowed if the necessary journal data does not exist on the primary storage system used for the Delta Resync operation.

Both
531 Common When PIN data is generated, the SIM currently stored in the SVP is reported to the host.

Mode 531 = ON: The SIM for PIN data generation is reported to the host along with being stored in the SVP.

Mode 531 = OFF (default): The SIM for PIN data generation is stored in SVP only, not reported to the host, the same as the current specification.

Both
548 ShadowImage for Mainframe from BCM

TrueCopy for Mainframe from BCM

Universal Replicator for Mainframe from BCM

This option prevents pair operations of TCz, URz, or SIz via Command Device used by BCM when Command Device satisfies the following conditions:

Mode 548 = ON: Pair operations of TCz, URz, or SIz via online Command Device are not available. SSB=0x64fb is output.

Mode 548 = OFF (default): Pair operations of TCz, URz, or SIz via online Command Device are available. SIM is output.

Notes:
  1. When Command Device is used online, if a script containing an operation via Command Device has been executed, the script may stop if this SOM is set to ON. As described in the BCM user’s guide, the script must be performed with Command Device offline.
  2. This SOM is applied to operations from BCM that is operated on MVS.
Both
556 Open Prevents an error code from being set in bytes 8 - 11 in the standard 16-byte sense byte.

Mode 556 = ON: An error code is not set in bytes 8 - 11 in the standard 16-byte sense byte.

Mode 556 = OFF (default): An error code is set in bytes 8 - 11 in the standard 16-byte sense byte.

Both
561 ShadowImage

Universal Volume Manager

Allows Quick Restore for external volumes with different Cache Mode settings.

Mode 561 = ON: Quick Restore for external volumes with different Cache Mode settings is prevented.

Mode 561 = OFF (default): Quick Restore for external volumes with different Cache Mode settings is allowed.

Both
573 TrueCopy for Mainframe

ShadowImage for Mainframe

For the CU emulation type 2105/2107, specifying the CASCADE option for the ICKDSF ESTPAIR command is allowed.

Mode 573 = ON: The ESTPAIR CASCADE option is allowed.

Mode 573 = OFF (default): The ESTPAIR CASCADE option is not allowed. (When specified, the option is rejected.)

Notes:
  1. When CU emulation type is 2105/2107, this SOM is applied in the case where pair creation in TCzSIz cascading configuration in the ICKDSF environment fails with the following message output:

    Message: ICK30111I DEVICE SPECIFIED IS THE SECONDARY OF A DUPLEX OR PPRC PAIR

  2. This SOM is applied when building an environment using the Metro Mirror F.O./F.B. function with TPC-R or CSM.
  3. The CASCADE option can be specified in the TSO environment also.
  4. Although the CASCADE option can be specified for the ESTPAIR command, the PPRC-XD function is not supported.
  5. Perform thorough pre-check for any influence on GDPS/PPRC.
  6. The SOM must be enabled only when the CASCADE option is specified for the ESTPAIR command for the CU emulation type 2105/2107.
Both

The unit for which TCz and SIz in a cascading configuration use the same volume.

589 Universal Volume Manager When this SOM is ON, the frequency of progress update of disconnection is changed.

Mode 589 = ON: For each external volume, progress is updated only when the progress rate is 100%.

Mode 589 = OFF (default): Progress is updated when the progress rate exceeds the previous level.

Notes:

  1. Set this SOM to ON when disconnecting an external volume while the specific host IO operation is online and its performance requirement is severe.
  2. Whether the disconnecting status for each external volume has progressed cannot be confirmed on Device Manager - Storage Navigator (it indicates "-"until just before the completion and then it changes to 100% at the very end).
Both
598 Universal Replicator for Mainframe This SOM is used to report SIMs (RC=DCE0 to DCE3) to a Mainframe host to warn that a URz journal is full.

Mode 598 = ON: SIMs (RC=DCE0 to DEC3) to warn that a JNL is full are reported to SVP and the host.

Mode 598 = OFF (default): SIMs (RC=DCE0 to DEC3) to warn that a JNL is full are reported to SVP only.

Notes:
  1. This SOM is applied if SIMs (RC=DCE0 to DCE3) need to be reported to a Mainframe host.
  2. The SIMs are not reported to the Open server.
  3. SIMs for JNL full (RC=DCE0 and DCE1) on MCU are reported to the host connected with MCU.
  4. SIMs for JNL full (RC=DCE2 and DCE3) on RCU are reported to the host connected with RCU.
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624 Universal Replicator The mode can be set to ON for storage systems in a CCI consistency group.

Mode 624 = ON: If 5 minutes have passed after time stamp updates from CCI stopped(*), pairs of journal groups on the storage systems with this mode set to ON are suspended due to failure (SIM=DC1XYY).

(*) The reason of the stop is unstable path status between the CCI server and the storage system in the primary site, or a stop of a CCI instance.

Mode 624 = OFF (default): Pairs are not suspended due to failure 5 minutes after time stamp updates from CCI have stopped.

Notes:
  1. Apply this SOM if suspending pairs, preventing journals from being accumulated, and notifying the error to users are preferred rather than allowing journal accumulation and eventual failure suspension due to journal full when the communication between CCI and the storage system in the primary site is unavailable in a consistency group configuration.
  2. When this SOM is set to ON, set the interval of issuing time stamps from CCI to 4 minutes or less (about 1 second is recommended). If greater than 4 minutes is set, the function may work 5 minutes after a temporary communication error, etc.
  3. To stop a CCI instance for 5 minutes or longer for CCI configuration definition file rewriting or server maintenance, set this SOM to OFF.
  4. If the DKCMAIN microcode is downgraded to an unsupported version while this SOM is set to ON, and then the microcode is to be upgraded to the supported version, set this SOM to OFF before the microcode upgrade.
MCU
632 TrueCopy for Mainframe This SOM is used to correct the reported data of PPRC QUERY when the PPRC ESTPAIR CRIT option is "NO" (fence level = NEVER) and VPD (SOM 36) is set to ON. By setting this SOM to ON/OFF when the PPRC ESTPAIR CRIT option is "NO" and VPD (SOM 36) is ON, Byte1,Bit5 (VPD flag) of PPRC QUERY is changed. PPRC QUERY display is not changed (CRIT (NO)).

Mode 632 = ON: Byte1,Bit5 (VPD flag) = ON

Mode 632 = OFF (default): Byte1,Bit5 (VPD flag) = OFF

For details, contact customer support (see the SOM632 sheet).

Notes:
  1. This SOM is applied if reporting Byte1,Bit5 (VPD flag) = ON when the PPRC ESTPAIR CRIT option is "NO" (Fence level = NEVER) and VPD (SOM36) is ON is required.
  2. The behavior of CRIT (=fence level) itself does not change and is the same as PPRC ESTPAIR CRIT (NO).
Both
640 TrueCopy for Mainframe

ShadowImage for Mainframe

VARY ONLINE can be run from the host for a volume shared by a TCz S-VOL (SwapSuspend or S-VOL write access permitted) and an SIz P-VOL. This SOM changes the behavior of the Sense SubSystem command from its current behavior to its previous behavior.

Mode 640 = ON (default): The SIz pair information is returned for the Sense SubSystem command that runs when either a TCz pair is in SSWS status or when write access to the S-VOL is permitted in a configuration where the TCz pair is combined with an SIz pair.

Mode 640 = OFF: . The SIz pair information is not returned (SIMPLEX) for the Sense SubSystem command that runs when either a TCz pair is in SSWS status or when write access to the S-VOL is permitted in a configuration where the TCz pair is combined with an SIz pair.

Notes:
  1. This SOM is applied to obtain the SIz pair information by the SenseSubSystem command when a TCz pair is in SSWS status or write access to the S-VOL is permitted in a configuration where the TCz pair is conbined with an SIz pair.
  2. When SOM 640 is ON, VARY ONLINE cannot be run for a volume shared by a TCz S-VOL and anSIz P-VOL volume.
RCU
665 Common This SOM disables the automatic log dump collection function that works when a hardware failure occurs to reduce the time to start failure analysis. A failure log created on a storage system triggers the function to start at a hardware failure.

Mode 665 = ON (default): The auto dump collection function is disabled.

Mode 665 = OFF: The auto dump collection function is enabled.

Note: This SOM is applied when disabling the automatic log dump collection function is required at a failure.

-
689 TrueCopy

TrueCopy for Mainframe

Global-active device

This SOM is used to slow down the initial copy and resync copy operations when the Write Pending rate on RCU exceeds 60%

Mode 689 = ON: The initial copy and resync copy operations are slowed down when the Write Pending rate on RCU exceeds 60%.

If the CLPR write pending rate where the initial copy target secondary volume belongs to is not over 60% but that of MP PCB where the S-VOL belongs to is over 60%, the initial copy operation is slowed down.

Mode 689 = OFF (default): The initial copy and resync copy operations are not slowed down when the Write Pending rate on RCU exceeds 60% (the same as before).

Notes:
  1. This SOM can be set online.
  2. The micro-programs on both MCU and RCU must support this SOM.
  3. This SOM should be set when requested by the user.
  4. Setting this SOM to ON is recommended when GAD is installed, as the performance degradation is more likely to occur due to active-active I/Os.
  5. If the Write Pending status remains at 60% or more on the RCU for a long time, it takes extra time for the initial copy and resync copy to be completed due to slowed down copy operations.
  6. If the Write Pending rate of CLPR to which the initial copy target S-VOL belongs is not over 60% but that of MP PCB to which the S-VOL belongs is over 60%, the initial copy operation is slowed down.
  7. When this SOM is applied while an unsupported model (USP V/VM earlier than V02) is connected as MCU, if the Write Pending rate reaches 60%, pair suspend may occur.
  8. As the mode is enabled per storage system, in an environment where TC and GAD are used, the mode is applied to both program products. When GAD is installed in a storage system that already uses TC, TC initial copy may take longer time.
Both
690 Universal Replicator

Universal Replicator for Mainframe

This SOM is used to prevent Read JNL or JNL Restore when the Write Pending rate on RCU exceeds 60% as follows:
  • When CLPR of JNL-Volume exceeds 60%, Read JNL is prevented.
  • When CLPR of Data (secondary)-Volume exceeds 60%, JNL Restore is prevented.

Mode 690 = ON: Read JNL or JNL Restore is prevented when the Write Pending rate on RCU exceeds 60%.

Mode 690 = OFF (default): Read JNL or JNL Restore is not prevented when the Write Pending rate on RCU exceeds 60% (the same as before).

Notes:
  1. This SOM can be set online.
  2. This SOM should be set per customer’s requests.
  3. If the Write Pending status long keeps 60% or more on RCU, it takes extra time for the initial copy to be completed by making up for the prevented copy operation.
  4. If the Write Pending status long keeps 60% or more on RCU, the pair status may become Suspend due to the JNL-Vol being full.
RCU
701 Universal Volume Manager This SOM is used to issue the Read command at the logical unit discovery operation using UVM.

Mode 701 = ON: The Read command is issued at the logical unit discovery operation.

Mode 701 = OFF (default): The Read command is not issued at the logical unit discovery operation.

Notes:
  1. When the external storage is TagmaStore USP/NSC and the Open LDEV Guard attribute (VMA) is defined on an external device, set this SOM to ON.
  2. When this SOM is set to ON, it takes longer time to complete the LU discovery. The amount of time depends on the external storage system.
  3. With this SOM OFF, if searching for external devices with VMA is set, the VMA information cannot be read.
  4. When this SOM is set to ON while the following conditions are met, the external volume is blocked:
    • An external volume to which Nondisruptive migration (NDM) attribute is set exists.
    • The external volume is reserved by the host
  5. As the VMA information is TagmaStore USP/NSC-specific, this SOM does not need to be ON when the external storage is other than TagmaStore USP/NSC.
  6. Set this SOM to OFF when an external volume to which nondisruptive migration (NDM) attribute is set exists.
-
704 ShadowImage

ShadowImage for Mainframe

Compatible FlashCopy®

Volume Migration

To reduce the chance of MIH, this SOM can reduce the priority of ShadowImage, Volume Migration, or Resync copy internal IO requests so that host IO has a higher priority. This SOM creates new work queues where these jobs can be assigned with a lower priority.

Mode 704 = ON: Copy processing requested is registered into a newly created queue so that the processing is scheduled with lower priority than host I/O.

Mode 704 = OFF (default): Copy processing requested is not registered into a newly created queue. Only the existing queue is used.

Notes:
  1. Apply this SOM when the load of host I/O to an ECC that uses ShadowImage or Volume Migration is high and the host I/O processing is delayed.
  2. If the PDEV is highly loaded, the priority of Read/Write processing made by ShadowImage, Volume Migration, or Resync may become lower. As a consequence the copy speed may be slower.
-
721 Common When a parity group is uninstalled or installed, the following operation is performed according to the setting of SOM 721.

Mode 721 = ON: When a parity group is uninstalled or installed, the LED of the drive for uninstallation is not illuminated, and the instruction message for removing the drive does not appear. Also, the windows other than that of parity group, such as DKA or DKU, are unavailable to select.

Mode 721 = OFF (default): When a parity group is uninstalled or installed, the LED of the drive is illuminated, and the drive must be unmounted and remounted.

Notes:
  1. When the RAID level or emulation type is changed for the existing parity group, this SOM should be applied only if the drive mounted position remains the same at the time of the parity group uninstallation or installation.
  2. After the operation using this SOM is completed, this SOM must be set back to OFF; otherwise, the LED of the drive to be removed will not be illuminated at subsequent parity group uninstalling operations.
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725 Universal Volume Manager This SOM determines the action that will be taken when the status of an external volume is Not Ready.

Mode 725 = ON: When Not Ready is returned, the external path is blocked and the path status can be automatically recovered (Not Ready blockade). Note that the two behaviors, automatic recovery and block, may be repeated.

When the status of a device is Not Ready blockade, Device Health Check is executed after 30 seconds.

Mode 725 = OFF (default): When Not Ready is returned 3 times in 3 minutes, the path is blocked and the path status cannot be automatically recovered (Response error blockade).

Notes:
  1. Applying this SOM is prohibited when USP V/VM is used as external storage system and its external volume is DP-VOL.
  2. Applying this SOM is recommended when the above condition (1) is not met and SUN storage is used as an external storage.
  3. Applying this SOM is recommended when the above condition (1) is not met and EMC CX series or Fujitsu Fibre CAT CX series is used as an external storage.
  4. Applying this SOM is recommended if the above condition (1) is not met and a maintenance operation such as firmware update causing controller reboot is executed on the external storage side while a storage system other than Hitachi product is used as an external storage system.
  5. While USP V/VM is used as an external storage system and its volume is DP-VOL, if some Pool-VOLs constituting the DP-VOL are blocked, external path blockade and recovery occurs repeatedly.
  6. When a virtual volume mapped by UVM is set to pool-VOL and used as DP-VOL in local storage system, this SOM can be applied without problem.
-
729 Dynamic Provisioning

Data Retention Utility

When a DP pool is full, if any write operation is requested to the area where the page allocation is not provided, this SOM can enable the DRU Protect attribute for the target DP-VOL.

Mode 729 = ON: Set the DRU Protect attribute for the target DP-VOL when any write operation is requested to the area where the page allocation is not provided at a time when the DP pool is full. (Not to set in the case of Read request.)

Mode 729 = OFF (default): Do not set the DRU Protect attribute for the target DP-VOL when any write operation is requested to the area where the page allocation is not provided at a time when DP pool is full.

For details, contact customer support (see SOM729 & 803 sheet).

Notes:

  1. This SOM is applied when:
    • The threshold of pool is high (for example, 95%) and the pool may be full.
    • DP-VOL uses a file system.
    • Data Retention Utility is installed.
  2. Since the Protect attribute is set for V-VOL, the Read operation cannot be allowed as well.
  3. When Data Retention Utility is not installed, the desired effect is not achieved.
  4. Protect attribute can be released from the Data Retention window of Device Manager - Storage Navigator after releasing the full status of the pool by adding a Pool-VOL.
  5. The VVP (Virtual Volume Protection) function can be enabled/disabled for each pool. With SOM 729 disabled, VVP is also disabled by default, but you can enable VVP for each pool as needed. With SOM 729 enabled, VVP is also enabled automatically (by default) when you create a new pool. Caution: A pool is NOT protected by ANY FUNCTION if you deliberately turn VVP for the pool from ON (default) to OFF, even with SOM 729 enabled.
  6. When HMO 63 or 73 is set to ON, the setting of the HMO is prioritized over the SOM 729 setting, so that the behavior remains the same as when SOM 729 is OFF even when it is set to ON.
-
734 Dynamic Provisioning

Dynamic Provisioning for Mainframe

When exceeding the pool threshold, the SIM is reported as follows:

Mode 734 = ON: A SIM is reported at the time when the pool usage rate exceeds the pool threshold (warning, system, or depletion). Once the pool usage rate falls below the pool threshold, and then exceeds again, the SIM is reported again. If the pool usage rate continues to exceed the warning threshold and the depletion threshold, the SIM (SIM-RC625000) is repeatedly reported every 8 hours until the pool usage rate falls below the depletion threshold.

Mode 734 = OFF (default): A SIM is reported at the time when the pool usage rate exceeds the pool threshold (warning, system, or depletion). Once the pool usage rate falls below the pool threshold, and then exceeds again, the SIM is reported again. The SIM is not reported while the pool usage rate continues to exceed the warning threshold and the depletion threshold.

Notes:
  1. This SOM is turned ON to prevent the write I/O operation from being unavailable due to pool full.
  2. If the pool threshold exceeding SIM occurs frequently, other SIMs may not be reported.
  3. Though turning on this SOM can increase the warning effect, if measures such as adding a pool fail to be done in time so that the pool becomes full, SOM 729 can be used to prevent file systems from being destroyed.
  4. Turning on SOM 741 can provide the SIM report to both the users and the service personnel.
  5. If SIM=62B000 remains uncompleted, the SIM is not reported to SVP.
-
741 Dynamic Provisioning

Dynamic Provisioning for Mainframe

This SOM enables to switch over whether to report the following SIM for users to the service personnel:

SIM-RC 625000 (DP pool usage rate continues to exceed the threshold)

Mode 741 = ON: SIM is reported to the service personnel.

Mode 741 = OFF (default): SIM is not reported to the service personnel.

Notes:
  1. This SOM is set to ON to have SIM for users reported to the service personnel:
    • For the system where SNMP and E-mail notification are not set.
    • If Device Manager - Storage Navigator is not periodically activated.
  2. When SOM 734 is turned OFF, SIM-RC625000 is not reported; accordingly the SIM is not reported to the service personnel even though this SOM is ON.
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745 Universal Volume Manager This SOM enables to change the area where the information is obtained as the Characteristic1 item from SYMMETRIX.

Mode 745 = ON:

  • The area where the information is obtained as the Characteristic1 item from SYMMETRIX is changed.
  • When CheckPaths or Device Health Check (1/hour) is performed, the information of an already-mapped external volume is updated to the one after change.

Mode 745 = OFF (default):

  • The area where the information is obtained as the Characteristic1 item from SYMMTRIX is set to the default.
  • When CheckPaths or Device Health Check (1/hour) is performed, the information of an already-mapped external volume is updated to the default.
Notes:
  1. This SOM is applied when the EMC SYMMETRIX is connected using UVM.
  2. Enable the setting of EMC SCSI Flag SC3 for the port of the EMC SYMMETRIX storage connected with the storage system and disable the setting of Flag SPC2. If the setting of EMC SCSI Flag SC3 is not enabled or the setting of Flag SPC2 is enabled, the effect of this SOM may not be achieved.
  3. If you want to enable this SOM immediately after setting, perform Check Paths on each path one by one for all the external ports connected to the EMC SYMMETRIX storage. But, without doing Check Paths, the display of Characteristic1 can automatically be changed by the Device Health Check to be performed once an hour. If SSB=AD02 occurs and a path is blocked, perform Check Paths on this path again.
  4. If the Check Paths is performed while ShadowImage for Mainframe pair and FlashCopy® Mirror pair are defined in the specified volume, the Check Paths operation is rejected with a message, "605 2518". If ShadowImage for Mainframe pair and FlashCopy® Mirror pair are defined in the specified volume, do not perform Check Paths but wait until the display is automatically changed.
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749 Dynamic Provisioning

Dynamic Provisioning for Mainframe

Dynamic Tiering

Dynamic Tiering for Mainframe

This SOM disables the DP Rebalance function that allows the drives of all ECC Groups in the pool to share the load.

Mode 749 = ON: The DP Rebalance function and the HDT Tier relocation function are disabled.

Mode 749 = OFF (default): The DP Rebalance function and the HDT Tier relocation function are enabled.

Notes:
  1. This SOM is applied when no change in performance characteristic is desired.
  2. When a pool is newly installed, the load may be concentrated on the installed pool volumes.
  3. When 0 data discarding is executed, load may be unbalanced among pool volumes.
  4. Pool VOL deletion while this SOM is set to ON fails. To delete pool VOLs, set this SOM to OFF.
-
757 Common Enables/disables output of in-band audit logs.

Mode 757 = ON: In-band audit log is not output.

Mode 757 = OFF (default): In-band audit log is output.

Notes:
  1. This SOM applies to the sites where outputting the In-band audit logs is not needed.
  2. When this SOM is set to ON:
    • There is no access to SM for the In-band audit logs, which can avoid the corresponding performance degradation.
    • SM is not used for the In-band audit logs.
  3. If outputting the In-band audit log is desired, set this SOM to OFF.
-
762 Universal Replicator for Mainframe This SOM enables to settle the data to RCU according to the time stamp specified in the command when a Flush suspension for an EXCTG is performed from BCM.

Mode 762 = ON: The data is settled to RCU according to the time stamp specified in the command.

Mode 762 = OFF (default): The data is settled to RCU according to the time stamp that RCU has received.

Notes:
  1. This SOM is applied under the following conditions.
    • Universal Replicator for Mainframe.
    • EXCTG configuration.
    • Flush suspension with an EXCTG specified is executed.
    • BCM is installed on the host where the time stamping function is available.
    • (In the case of multiple-host configuration, SYSPLEX timer is available on the system)
  2. If this SOM is set to ON while the BCM does not exist in the environment where the time stamping function is available (In the case of multiple-host configuration, SYSPLEX timer is available on the system), the pair status may not become Suspend after Flush suspension for an EXCTG.
  3. Do not set this SOM to ON if the BCM does not exist in the environment where the time stamping function is available (In the case of multiple-host configuration, SYSPLEX timer is available on the system).
Both

(On RCU side, consideration in Takeover is required for setting)

769 TrueCopy

TrueCopy for Mainframe

Universal Replicator

Universal Replicator for Mainframe

This SOM controls whether the retry operation is executed or not when a path creation operation is executed.

(The function applies to both of CU FREE path and CU single path for Open and Mainframe).

Mode 769 = ON: The retry operation is disabled when the path creation operation is executed (retry operation is not executed).

Mode 769 = OFF (default): The retry operation is enabled when the path creation operation is executed (retry operation is executed).

Apply this SOM when the Basic HyperSwap® function of TPC-R or CSM is used. The Basic HyperSwap® function can allow the CESTPATH operation to establish a path to several secondary systems at the same time. Because attributes of a port are switched if the CESTPATH operation is performed with SOM 144 ON, the path status between the primary and secondary systems is changed to linkdown. If the CESTPATH operation is performed to two or more secondary systems at the same time, MIH may be reported to a host as the other CESTPATH operation, which has detected the linkdown path, retries the CESTPATH operation. To disable an MIH report to a host, set this SOM to ON to disable the CESTPATH to retry the operation when a linkdown is detected.

Notes:
  1. Apply this SOM when the following three conditions are met:
    • SOM 114 is set to OFF (operation of automatically switching the port is disabled).
    • HMO 49 and HMO 50 are set to OFF.
    • TPC-R or CSM is used (it is not applied in normal operation).
  2. When SOM 769 is set to ON, SOM 114, HMO 49, and HMO 50 must be set to OFF.
  3. In either of the following cases, the path creation operation might fail after automatic port switching is executed.
    • SOM 114 is set to ON.
    • HMO 49 and HMO 50 are set to ON.
Both
776 TrueCopy for Mainframe

Business Continuity Manager

This SOM enables/disables to output the F/M = FB message to the host when the status of the P-VOL changes to Suspend during a TCz S-VOL pair suspend or pair delete operation from Business Continuity Manager.

Mode 776 = ON: When the status of P-VOL changes to Suspend during a TCz S-VOL pair suspend or delete operation from BCM, the F/M=FB message is not output to the host.

Mode 776 = OFF (default): When the status of P-VOL changes to Suspend during a TCz S-VOL pair suspend or delete operation from BCM, the F/M=FB message is output to the host.

Notes:
  1. Set this SOM to ON in the environment where TCz is used from BCM and the MCU host does not need the F/M=FB message output during an S-VOL pair suspend or pair delete operation from BCM.
  2. When this SOM is set to ON, the F/M=FB message is not output to the host when the status of P-VOL changes to Suspend during a TCz S-VOL pair suspend or pair delete operation from BCM.
  3. If the PPRC item of CU option is set to NO, the F/M=FB message is not output to the host regardless of setting of this SOM.
  4. If the function switch#07 is set to "enable", the F/M=FB message is not output to the host regardless of setting of this SOM.
Both
784 TrueCopy

TrueCopy for Mainframe

Global-active device

This SOM can reduce the MIH watch time of RI/O for a TC, TCz, or GAD pair internally so that update I/Os can continue by using an alternate path without MIH or time-out occurrence in the environment where Mainframe host MIH is set to 15 seconds, or Open host time-out time is short (15 seconds or less). This SOM is effective at initial pair creation or Resync operation for TC, TCz, or GAD. (Not effective by just setting this SOM to ON.)

This SOM is applied to TC, TCz, and GAD. This SOM supports Fibre Channel remote copy paths but not iSCSI.

Mode 784 = ON: The MIH time of RIO is internally reduced so that, even though a path failure occurs between storage systems in the environment where host MIH time is set to 15 seconds, update I/Os can be processed by using an alternate path promptly, lowering the possibility of host MIH occurrence.

Mode 784 = OFF (default): The operation is processed in accordance with the TC, TCz, or GAD specification.

Notes:
  1. This SOM is applied to the environment where Mainframe host MIH time is set to 15 seconds.
  2. This SOM is applied to the environment where OPEN host time-out time is set to 15 seconds or less.
  3. This SOM is applied to reduce RI/O MIH time to 5 seconds.
  4. This function is available for all the TC, TCz, and GAD pairs on the storage system, unable to specify the pairs that are using this function or not.
  5. To apply this SOM to TCz, MCU and RCU must be USP V/VM or later models and micro-program must be the support version on both sides.
  6. For a TC, TCz, or GAD pair with this SOM effective (RI/O MIH time is 5 seconds), the setting of RI/O MIH time made at RCU registration (default is 15 seconds, which can be changed within range from 10 to 100 seconds) is invalid. However, RI/O MIH time displayed on Device Manager - Storage Navigator and CCI is not "5 seconds" but is what set at RI/O registration.
  7. If a failure occurs on the switched path between storage systems, Mainframe host MIH or Open server time-out may occur.
  8. If an MP to which the path between storage systems belongs is overloaded, switching to an alternate path delays and host MIH or time-out may occur.
  9. If an RI/O retry occurs due to other factors than RI/O MIH (5 sec), such as a check condition report issued from RCU to MCU, the RI/O retry is performed on the same path instead of an alternate path. If a response delay to the RI/O occurs constantly on this path due to path failure or link delay, host MIH or time-out may occur due to response time accumulation for each RI/O retried within 5 seconds.
  10. Even though this SOM is set to ON, if Mainframe host MIH time or Open host time-out time is set to 10 seconds or less, host MIH or time-out may occur due to a path failure between storage systems.
  11. Operation commands are not available for promptly switching to an alternate path.
  12. This SOM works for the pair for which initial pair creation or Resync operation is executed.
  13. Micro-program downgrade to an unsupported version cannot be executed unless all the TC, TCz, and GAD pairs are suspended or deleted.
  14. For operational specifications in each combination of MCU and RCU of TCz/TC, contact customer support (see SOM784 sheet).
  15. For GAD pairs, this SOM is effective if the microcode version supports GAD.
  16. This SOM does not support iSCSI paths between storage systems. When iSCSI is used for paths between storage systems, the time to switch to an alternate path cannot be reduced. For this, if a failure occurs on a path between storage systems in an environment where host time-out time is short, a time-out may occur on the host side. A time-out may also occur on the host side when a failure occurs on an iSCSI path between storage systems if storage system paths of Fibre and iSCSI coexist in an environment where host time-out time is short so that the configuration where storage system paths of Fibre and iSCSI coexist is not supported too.
Both
787 Compatible FlashCopy® V2 This SOM enables the batch prefetch copy.

Mode 787 = ON: The batch prefetch copy is executed for an FCv2 pair and a Preserve Mirror pair.

Mode 787 = OFF (default): The batch prefetch copy is not executed.

Notes:
  1. When this SOM is set to ON, the performance characteristic regarding sequential I/Os to the FCv2 target VOL changes.
  2. This SOM is applied only when SOM 577 is set to OFF.
  3. This SOM is applied if response performance for a host I/O issued to the FCv2 target VOL is prioritized.
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789 ShadowImage This SOM enables you to temporarily stop the copy processing caused by the I/O from the host server to the P-VOL when the load on the storage system is high. Degradation of I/O performance on the volumes that belong to the copy target CLPR is suppressed to the minimum.

Mode 789 = ON (default): If the Write Pending rate of the MP unit to which the copy target CLPR belongs is 70% or higher, the copy processing caused by the I/O from the host server to the P-VOL is suppressed.

Mode 789 = OFF: If the Write Pending rate of the MP unit to which the copy target CLPR belongs is in the following status, the copy processing caused by the I/O on the P-VOL is suppressed. Note that, if the Write Pending rate is high, the I/O performance on the volumes that belong to the copy target CLPR might be degraded.

For DKCMAIN 93-05-06 and earlier, 93-06-01 to 93-06-03, 93-06-21 to 93-06-23, and 93-06-41:

  • When the capacity saving function is enabled on the P-VOL or S-VOL, copy processing is suppressed when the Write Pending rate is 75% or more.
  • When the capacity saving function is not enabled on the P-VOL or S-VOL, copy processing is not suppressed regardless of the Write Pending rate.

For DKCMAIN 93-05-07 and later, 93-06-04 and later, 93-06-24 and later, and 93-06-42 and later:

  • When the capacity saving function is enabled on the P-VOL or S-VOL and any host I/O priority mode 1 to 5 (local replica options) is enabled, copy processing is suppressed when the Write Pending rate is 70% or more.
  • When the capacity saving function is enabled on the P-VOL or S-VOL and none of the host I/O priority modes is enabled, copy processing is suppressed when the Write Pending rate is 75% or more.
  • When the capacity saving function is disabled on the P-VOL and S-VOL, copy processing is suppressed when the Write Pending rate is 90% or more.
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790 ShadowImage This SOM enables you to temporarily stop the copy processing caused by the I/O from the host server to the S-VOL when the load on the storage system is high. Degradation of I/O performance on the volumes that belong to the copy target CLPR is suppressed to the minimum.

Mode 790 = ON (default): When the Write Pending rate of the MP unit that the copy target CLPR belongs to is 60% or more, the copy processing caused by the I/O from the host server to the S-VOL is suppressed.

Mode 790 = OFF: When the Write Pending rate of the MP unit that the copy target CLPR belongs to is in the following status, the copy processing caused by the I/O on the S-VOL is suppressed. Note that, if theWrite Pending rate is high, the I/O performance on the volumes that belong to the copy target CLPR might be degraded.

For DKCMAIN 93-05-06 and earlier, 93-06-01 to 93-06-03, 93-06-21 to 93-06-23, and 93-06-41:

  • When the capacity saving function is enabled on the P-VOL or S-VOL, copy processing is suppressed when the Write Pending rate is 75% or more.
  • When the capacity saving function is not enabled on the P-VOL or S-VOL, copy processing is not suppressed regardless of the Write Pending rate.

For DKCMAIN 93-05-07 and later, 93-06-04 and later, 93-06-24 and later, and 93-06-42 and later:

  • When the capacity saving function is enabled on the P-VOL or S-VOL, copy processing is suppressed when the Write Pending rate is 75% or more.
  • When the capacity saving function is disabled on the P-VOL or S-VOL, copy processing is suppressed when the Write Pending rate is 90% or more.
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803 Dynamic Provisioning

Data Retention Utility

While a DP pool VOL is blocked, if a read or write I/O is issued to the blocked pool VOL, this SOM can enable the Protect attribute of DRU for the target DP-VOL.

Mode 803 = ON: While a DP pool VOL is blocked, if a read or write I/O is issued to the blocked pool VOL, the DRU attribute is set to Protect.

Mode 803 = OFF (default): While a DP pool VOL is blocked, if a read or write I/O is issued to the blocked pool VOL, the DRU attribute is not set to Protect.

For details, contact customer support (see SOM729 & 803 sheet).

Notes:
  1. This SOM is applied when:
    • A file system using DP pool VOLs is used.
    • Data Retention Utility is installed.
  2. Because the DRU attribute is set to Protect for the V-VOL, read I/Os are also disabled.
  3. If Data Retention Utility is not installed, the expected effect cannot be achieved.
  4. The Protect attribute of DRU for the DP V-VOL can be released on the Data Retention window of Device Manager - Storage Navigator after recovering the blocked pool VOL.
  5. The VVP (Virtual Volume Protection) function when the pool volume is blocked is supported. VVP can be enabled/disabled for each Pool.

    With SOM 803 disabled, VVP when the pool volume is blocked is also disabled by default. But you can enable VVP for each pool whenever you want.

    With SOM 803 enabled, VVP when the pool volume is blocked is also enabled automatically (by default) when you create a new pool.

    Caution: A pool is NOT protected by ANY FUNCTION if you deliberately change VVP for the pool from ON (default) to OFF, even with SOM 803 enabled.

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855 ShadowImage

ShadowImage for Mainframe

Volume Migration

By switching this SOM to ON/OFF when ShadowImage is used with SOM 467 set to ON, copy processing is continued or stopped as follows.

Mode 855 = ON: When the amount of dirty data is within the range from 58% to 63%, the next copy processing is continued after the dirty data created in the previous copy is cleared to prevent the amount of dirty data from increasing (copy after destaging). If the amount of dirty data exceeds 63%, the copy processing is stopped.

Mode 855 = OFF (default): The copy processing is stopped when the amount of dirty data is over 60%.

For details, contact customer support (see SOM855 sheet).

Notes:
  1. This SOM is applied when all the following conditions are met
    • ShadowImage is used with SOM 467 set to ON.
    • Write pending rate of an MP unit that has LDEV ownership of the copy target is high
    • Usage rate of a parity group to which the copy target LDEV belongs is low.
    • ShadowImage copy progress is delayed.
  2. This SOM is available only when SOM 467 is set to ON.
  3. If the workload of the copy target parity group is high, the copy processing may not be improved even if this SOM is set to ON.
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867 Dynamic Provisioning

Dynamic Tiering

All-page reclamation (discarding all mapping information between DP pool and DP volumes) is executed in DP-VOL LDEV format. This new method is enabled or disabled by setting this SOM to ON or OFF.

Mode 867 = ON (default): LDEV format of the DP-VOL is performed with page reclamation.

Mode 867 = OFF:LDEV format of the DP-VOL is performed with 0 data writing.

Notes:
  1. This SOM is applied from factory shipment.
  2. Do not change the setting of this SOM during DP-VOL format.
  3. If the setting of this SOM is changed during DP-VOL format, the change is not reflected to the format of the DP-VOL being executed but the format continues in the same method.
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895 TrueCopy for Mainframe Setting this SOM to ON or OFF, the link type with transfer speed of 8 Gbps/16 Gbps or 4 Gbps is reported respectively.

Mode 895 = ON (default): When the FICON®/FC link up speed is 8 Gbps/16 Gbps, the link type with transfer speed of 8 Gbps/16 Gbps is reported.

Mode 895 = OFF: The link type with transfer speed of up to 4 Gbps is reported , even when the actual transfer speed is 8 Gbps/16 Gbps.

Notes:
  1. To apply this SOM, the RMF version of mainframe z/OS® to be connected must be 1.12 or higher.
  2. If the OS does not use a supported version, the transfer speed cannot be displayed correctly.
  3. If all RMF versions of mainframe z/OS connected are 1.12 or higher, set this SOM to ON.
  4. If any version of mainframe z/OS connected is lower than 1.12, set this SOM to OFF.
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896 Dynamic Provisioning

Dynamic Provisioning for Mainframe

Dynamic Tiering

Dynamic Tiering for Mainframe

Thin Image

This SOM enables or disables the background format function performed on an unformatted area of a DP/DT/TI pool.

For information regarding operating conditions, see the Provisioning Guide.

Mode 896 = ON (default): The background format function is enabled.

Mode 896 = OFF: The background format function is disabled.

Notes:
  1. This SOM is applied when you need to disable the background format for a DP/DT/TI pool due to a concern of performance degradation of other functions in an environment where a DP-VOL is used by other functions.
  2. When the background format function is enabled, because up to 42 MB/s of ECCG performance is used, local copy performance may degrade by about 10%. Therefore, confirm whether the 10% performance degradation is acceptable or not before enabling the function.
  3. When a Dynamic Provisioning VOL on an external storage system, which is used as an external VOL, is used as a pool VOL, if the external pool on the external storage side becomes full due to the background format, the external VOL may be blocked.

    If the external pool capacity is smaller than the external VOL capacity (Dynamic Provisioning VOL of external storage system), do not enable the background format function.

  4. When a Dynamic Provisioning VOL on an external storage system, which is used as an external VOL, is used as a pool VOL, if the external pool on the external storage side becomes full due to the background format, the external VOL may be blocked.

    If the external pool capacity is smaller than the external VOL capacity (Dynamic Provisioning VOL of external storage system), do not enable the background format function.

  5. If the background format function is disabled by changing this SOM setting, the format progress is initialized and the entire area becomes unformatted.
  6. This SOM is set to ON before shipment.
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899 Volume Migration In combination with the SOM 900 setting, this SOM determines whether to execute and when to start the I/O synchronous copy change as follows.
Mode 899 = ON (default):
  • SOM 900 is ON: I/O synchronous copy starts without retrying Volume Migration.
  • SOM 900 is OFF: I/O synchronous copy starts when the threshold of Volume Migration retry is  exceeded. (Recommended)
Mode 899 = OFF:
  • SOM 900 is ON: I/O synchronous copy starts when the number of retries reaches half of the threshold of Volume Migration retry.
  • SOM 900 is OFF: Volume Migration is retired and I/O synchronous copy is not executed.
Notes:
  1. This SOM is applied when improvement of Volume Migration success rate is desired under the condition that there are many updates to a migration source volume of Volume Migration.
  2. During I/O synchronous copy, host I/O performance degrades.
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900 Volume Migration In combination with SOM 899 setting, this SOM determines whether to execute and when to start the I/O synchronous copy change as follows.
Mode 900 = ON:
  • SOM 899 is ON: I/O synchronous copy starts without retrying Volume Migration.
  • SOM 899 is OFF: I/O synchronous copy starts when the number of retries reaches half of the threshold of Volume Migration retry.
Mode 900 = OFF (default):
  • SOM 899 is ON: I/O synchronous copy starts when the threshold of Volume Migration retry is exceeded. (Recommended)
  • SOM 899 is OFF: Volume Migration is retired and I/O synchronous copy is not executed.
Notes:
  1. This SOM is applied when improvement of Volume Migration success rate is desired under the condition that there are many updates to a migration source volume of Volume Migration.
  2. During I/O synchronous copy, host I/O performance degrades.
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901 Dynamic Tiering

Dynamic Tiering for Mainframe

By setting this SOM to ON or OFF, the page allocation method of Tier Level ALL when the drive type of tier1 is SSD changes as follows.

Mode 901 = ON: For tier1 (drive type is SSD), pages are allocated until the capacity reaches the limit. Without consideration of exceeding performance limitation, allocation is done from highly loaded pages until reaching the capacity limit

When the capacity of tier1 reaches the threshold value, the minimum value of the tier range is set to the starting value of the lower IOPH zone, and the maximum value of the lower tier range is set to the boundary value.

Mode 901 = OFF (default): For tier1 (drive type is SSD), page allocation is performed based on performance potential limitation. With consideration of exceeding performance limitation, allocation is done from highly loaded pages but at the point when the performance limitation is reached, pages are not allocated any more even there is free space.

When the capacity of tier1 reaches the threshold value, the minimum value of the tier range is set to the boundary value, and the maximum value of the lower tier range is set to a value of boundary-value × 110% + 5 [IOPH].

Notes:
  1. This SOM is applied when pages with the maximum capacity need to be allocated to tier1 (drive type is SSD) with Dynamic Tiering or Dynamic Tiering for Mainframe.
  2. When Tier1 is SSD while SOM 901 is set to ON, the effect of SOM 897 and 898 to the gray zone of Tier1 and Tier2 is disabled and the SOM 901 setting is enabled instead. In addition, the settings of SOM 897 and 898 are effective for Tier2 and Tier3.
  3. The following is recommended when applying SOM 901:

    [actual I/O value (total number of I/Os of all tiering policies)] < [performance potential value of Tier1* × 0.6]

    * The performance potential value of Tier1 displayed on Monitor information by using Dx-ray. For details, contact customer support (see SOM897_898_901 sheet).

For more details about the interactions between SOMs 897, 898, and 901, contact customer support (see SOM897_898_901 sheet).

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904 Dynamic Tiering

Dynamic Tiering for Mainframe

By setting this SOM to ON or OFF, the number of pages to be migrated per unit time at tier relocation is changed.

Mode 904 = ON: The number of pages to be migrated at tier relocation is set to up to one page per second.

Mode 904 = OFF (default):No restriction on the number of pages to be migrated at tier relocation (existing specification).

Notes:
  1. This SOM is applied when:
    • Dynamic Tiering for Mainframe is used (including multi-platform configuration).
    • The requirement for response time is severe.
  2. The number of pages to be migrated per unit time at tier relocation decreases.
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908 Universal Replicator

Universal Replicator for Mainframe

This SOM can change CM capacity allocated to MPBs with different workloads.

Mode 908 = ON: The difference in CM allocation capacity among MPBs with different workload is large.

Mode 908 = OFF (default): The difference in CM allocation capacity among MPBs with different workload is small (existing operation) .

Notes:
  1. If a CLPR is used by only some MPBs among all the installed MPBs, set this SOM to ON for the CLPR to increase CM capacity allocated to the MPBs that use the CLPR.

    Example:

    (a) A CLPR only for UR JNLG.

    (b) A configuration where MPBs and CLPRs are separately used for Open and Mainframe systems.

  2. Since CM capacity allocated to MPBs with low load is small, the performance is affected by a sudden increase in load.
  3. SOM 908 cannot be used with SOM 933. When SOM 933 is set to ON, the function of SOM 908 is canceled even though SOM 908 is ON.
  4. This SOM is effective for a CLPR. Therefore, when setting this SOM to ON/OFF, select target "LPRXX (XX=00 to 31)". For example, even when CLPR0 is defined (any of CLPR1 to 31 are not defined), select "LPR00" first and then set this SOM to ON/OFF.
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930 Dynamic Provisioning

Dynamic Tiering

ShadowImage

When this SOM is set to ON, all of the zero data page reclamation operations in processing are stopped. (Also the zero data page reclamation cannot be started.)

* Zero data page reclamation by WriteSame and UNMAP functions, and IO synchronous page reclamation are not disabled.

Mode 930 = ON: All of the zero data page reclamation operations in processing are stopped at once. (Also the zero data reclamation cannot be newly started.)

Mode 930 = OFF (default): The zero data page reclamation is performed.

For details about interactions with SOM 755 and SOM 859, contact customer support (see SOM930 sheet).

Notes:
  1. This SOM is applied when stopping or disabling zero data page reclamation by user request is required.
  2. When this SOM is set to ON, the zero data page reclamation does not work at all.

    * Zero data page reclamation by WriteSame and UNMAP, IO synchronous page reclamation, program product synchronous page reclamation, and UDSR page reclamation can work.

  3. When downgrading micro-program to a version that does not support this SOM while this SOM is set to ON, set this SOM to OFF after the downgrade.

    * Because the zero data page reclamation does not work at all while this SOM is set to ON.

  4. This SOM is related to SOM 755 and SOM 859. For relationship with SOM755 and SOM859, contact customer support (see SOM930 sheet).
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937 1069 Dynamic Provisioning

Dynamic Provisioning for Mainframe

Dynamic Tiering

Dynamic Tiering for Mainframe

By setting this SOM to ON, HDT monitoring data is collected even if the pool is a DP pool.

Mode 937 = ON: HDT monitoring data is collected even if the pool is a DP pool.

Only Manual execution mode and Period mode are supported.

Mode 937 = OFF (default): HDT monitoring data is not collected if the pool is a DP pool

Notes:
  1. This SOM is applied when HDT monitoring data collection is required in DP environment.
  2. When HDT is already used, do not set this SOM to ON.
  3. For HDT monitoring data collection, shared memory for HDT must be installed. For details, contact customer support (see SOM937 sheet).
  4. If monitoring data collection is performed without shared memory for HDT installed, an error is reported and the monitoring data collection fails.
  5. Before removing the shared memory for HDT, set this SOM to OFF and wait for 30 minutes.
  6. Tier relocation with monitoring data collected when this SOM is set to ON is disabled.
  7. When DP is converted into HDT (after purchase of software license), the collected monitoring data is discarded.
  8. Before downgrading the micro-program to an unsupported version, set SOM 937 to OFF and wait for at least 30 minutes.
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972 Common By setting this SOM, THP Page Size in Inquiry Page E3h is changed. THP Page Size varies depending on the combination of SOM 972 and 973 settings as follows.

Mode 972 = ON: When SOM 972 is ON, the THP page size is 0x200 (256KB) regardless of the SOM 973 setting.

Mode 972 = OFF (default):
  • When SOM 972 and SOM 973 are both OFF, the THP page size is 0x15000 (42MB).
  • When SOM 972 is OFF and SOM 973 is ON, the THP page size is 0x10 (8KB).
Notes:
  1. This SOM is applied when a delay in host I/O response due to reclamation processing occurs in a customer environment.
  2. Reclamation processing is delayed.
  3. This SOM is to prioritize host I/O response over reclamation processing in VxVM environment, so that the time required for reclamation processing may increase when this SOM is set to ON.

For details about the interaction between this SOM and SOM 1069, contact customer support (see SOM1069 sheet).

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973 Common By setting this SOM, THP Page Size in Inquiry Page E3h is changed. THP Page Size varies depending on the combination of SOM972 and 973 settings as follows.

Mode 973 = ON:

  • When SOM 973 and SOM 972 are both ON, the THP page size is 0x200 (256KB).
  • When SOM 973 is ON and SOM 972 is OFF, the THP page size is 0x10 (8KB).

Mode 973 = OFF (default):

  • When SOM 973 and SOM 972 are both OFF, the THP page size is 0x15000 (42MB).
  • When SOM 973 is OFF and SOM 972 is ON, the THP page size is 0x200 (256KB).
Notes:
  1. This SOM is applied when a delay in host I/O response due to reclamation processing occurs in a customer environment.
  2. When this SOM is set to ON, reclamation processing is delayed.
  3. This SOM is to prioritize host I/O response over reclamation processing in VxVM environment, so that the time required for reclamation processing may increase when this SOM is set to ON.

For details about the interaction between this SOM and SOM 1069, contact customer support (see SOM1069 sheet).

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1021 Universal Volume Manager This SOM can enable or disable the auto-recovery for external volumes of an EMC storage system.

Mode 1021 = ON: An external volume that is blocked due to Not Ready status can be recovered automatically regardless of the type of external storage system.

Mode 1021 = OFF (default): An external volume that is blocked due to Not Ready status might not be recovered automatically depending on the type of external storage system.

Notes:
  1. This SOM is applied when the auto-recovery of external volumes that are blocked due to Not Ready status is desired in UVM connection using an ECM storage system as an external storage system.
  2. When this SOM is set to ON and the connected external storage system is not in stable status (such as failure and recovery from failure), a blockage due to Not Ready status and auto-recovery might occur repeatedly.
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1043 Universal Replicator

Universal Replicator for Mainframe

This SOM disables journal copy.

Mode 1043 = ON: When the following conditions are met at the UR secondary site, the journal copy is disabled.

The following conditions (a) and (b) or (a) and (c) are met:

(a) 4,096 or more journals are accumulated at the secondary site.

(b) The CLPR write pending rate for journal volumes of MP unit for which journal ownership at the RCU is defined is 25% or higher (including the write pending rate for other than journal volumes).

(c) It takes 15 seconds or longer to start restore after journal copy at the RCU.

Note: Even though the above conditions are met, journal copy is not disabled when all time stamps of the journals accumulated are the same in a consistency group containing multiple journals.

Mode 1043 = OFF (default): The journal copy is not disabled.

Notes:
  1. This SOM applies when one of the following conditions is met:
    1. Multiple journals are registered in a consistency group of CCI.
    2. Multiple journals are registered in an extended consistency group.
    3. Journals are accumulated at the secondary site, causing the system performance to decrease.
  2. If SOM 690 is set to ON and the Write Pending rate is 60% or higher, the journal copy is disabled regardless of the setting of this SOM.
  3. When the host write speed is faster than the JNL copy speed, the usage rate of the master journal increases.
  4. This SOM is effective within the range of each CLPR. Therefore, an operation target LPRxx (xx= 00 to 31) needs to be selected before setting this SOM to ON/OFF.

    For example, when setting this SOM only to CLPR0 (even though this SOM is not set to CLPR 1 to 31), select "LPR00" and then set this SOM to ON/OFF. If "System" is selected and then this SOM is set to ON, this SOM is not effective for any of the CLPRs.

  5. Set SOM 1043 to ON when journals are not accumulated at the RCU. If journals have already been accumulated at the RCU, journal copy does not start until the journal usage rate becomes 0%. (If you need to set SOM 1043 to ON while journals are accumulated, set Purge Suspend, and then perform resync.)
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1061 Compatible FlashCopy® V2

Compatible FlashCopy® SE

This SOM is used to enable the copy after write (CAW) function of Compatible FlashCopy®.

By setting this SOM to ON, CAW (While copy processing is withheld, command response is returned first and then the copy is done in asynchronous manner) can work so as to improve random write response performance. (In the case of sequential write, as an improvement to copy data in advance has been implemented, the equal performance can be achieved without CAW.)

Mode 1061 = ON: The CAW function works.

Mode 1061 = OFF (default): The CAW function does not work. (COW works.)

Notes:
  1. This SOM is applied when the CAW function is enabled.
  2. The cache write pending rate may increase.
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1067 Universal Replicator

Universal Replicator for Mainframe

This SOM is used to enable microcode downgrade to a version that does not support URxUR (including delta).

Mode 1067 = ON: Even when a UR pair has been registered, downgrading the microcode to a version that does not support URxUR (including delta) is allowed.

Mode 1067 = OFF (default): If any UR pair has been registered, downgrading the microcode to a version that does not support URxUR (including delta) is not allowed.

Notes:
  1. This SOM is applied to enable microcode downgrade to a version that does not support URxUR (including delta) if the configuration where any UR pair has been registered is not URxUR (including delta).
  2. Setting this SOM to ON allows microcode downgrade at sites where only 1 mirror is used in URxUR multi-target configuration without delta resync and cascade configuration (L or R site in multi-target, and P or R site in cascade), but the following phenomena occur after microcode downgrade. Make sure that the target storage system does not contain pairs of URxUR configuration.
    Phenomena:
    1. When the microcode is downgraded at S site (local or remote) in multi-target configuration, the pair between P site and the target S site cannot be resynchronized.
    2. When the pair between I site and R site in cascade configuration is resynchronized, the pair status cannot change from COPY to PAIR.
    3. When the microcode is downgraded at R site in cascade configuration, the pair between I site and R site cannot be resynchronized.
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1068 Common This mode can detect and report a minor drive response delay early by severely checking drives.

Mode 1068 = ON (default): Drive response delay is checked and detected with conditions that are more severe than current conditions.

When SOM 144 is set to ON, the drive with response delay is blocked.

Target drive: HDD, FMD, SSD

Mode 1068 = OFF: Drive response delay is checked and detected with current conditions.

The behavior varies depending on the combinations of SOM settings. For details, contact customer support (see SOM144 sheet).

Notes:
  1. Apply this mode to detect a minor delay in drive response.
  2. When a delay is suspected, a processing to refer to the statistics data and determine the delay works.
  3. If SOM 157 is set to ON, the output prevention status of SSB=A4CE is not cleared in one-day cycle.
  4. When applying this SOM only, a SIM for delay detection is reported but the drive is not blocked. To block the drive, SOM 144 also needs to be applied.
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1069 Common By setting this SOM, the INQUIRY Page E3h field is changed. The field varies depending on the combination of SOMs 972, 973, and 1069 as shown in the table below.

The default setting for SOM 1069 is OFF.

Notes:
  1. This SOM is applied when the page problem occurs in an environment where Symantec ASL 6.0.5 or higher is used and SOM 972 and/or 973 is set to ON.
  2. When this SOM is set to ON, reclamation processing is delayed.
  3. The priority of setting when SOMs are set at the same time is SOM 1069, SOM 972, and then SOM 973. The setting of higher priority SOM is enabled.
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table showing behavior of SOMs 972, 973, and 1069

 
1070 Global-active device This SOM changes the processing for a group operation with GAD consistency group (CTG).

Mode 1070 = ON: The status change of all pairs in a consistency group is performed for 50 msec.

Mode 1070 = OFF (default): The status change of all pairs in a consistency group is performed for 1 msec.

Notes:
  1. This SOM is applied when reducing the time to complete status change of all pairs in a consistency group at a group operation (suspension and resync operation) with the GAD CTG function. In a system configuration where host I/O performance is prioritized, do not use this SOM because setting this SOM may affect the host I/O performance.
  2. The MP usage rate increases during status change of all pairs in a consistency group. For details about approximate percentage increase in MP usage rate, contact customer support (see SOM1070 sheet).
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1080 Global-active device

Universal Volume Manager

This SOM is intended for a case that multiple external connection paths are connected to a Target port on an external system with a quorum disk and there is a path whose performance degrades. For such a case, this SOM can eliminate impacts on commands run for other external devices that share the Target port with the quorum disk on the external system by setting the time to run a reset command for the Target port to be the same (15 seconds) as that to run other commands for the other external devices.

Mode 1080 = ON: The time to run the reset command for the quorum disk on the external system is 15 seconds to eliminate the impacts on commands run for the other external devices that share the Target port with the quorum disk on the external system.

If a response to ABTS is delayed for 12 seconds or longer, the quorum disk may be blocked.

Mode 1080 = OFF (default): The time to run a reset command for the quorum disk when performance of a path degrades is 3 seconds so that a retry is performed by an alternate path to avoid quorum disk blockage.

Notes:
  1. The mode is applied if avoiding impacts on commands for other external devices that share a Target port on an external system side with a quorum disk is prioritized over preventing quorum disk blockage when a response to ABTS is delayed due to path performance degradation in a configuration where the Target port is shared between external devices and the quorum disk.
  2. When connection performance degradation occurs, the quorum disk blockage is more likely to occur.
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1083 Dynamic Provisioning

Universal Volume Manager

This SOM enables or disables DP-VOL deletion while an external volume associated with the DP-VOL with data direct mapping attribute is not disconnected.

Mode 1083 = ON: DP-VOL deletion is enabled.

Mode 1083 = OFF (default): DP-VOL deletion is disabled.

Notes:
  1. This SOM is applied when the following conditions are met.
    • A DP-VOL with data direct mapping attribute is deleted.
    • The data of external volume with data direct mapping attribute associated with a deletion target DP-VOL with data direct mapping attribute will not be used again.
  2. When SOM 1083 is set to ON, the data of external volumes cannot be guaranteed.
  3. When DP-VOL deletion is performed without disconnecting an external volume, the data of the external volume cannot be guaranteed.
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1086 Dynamic Provisioning

Dynamic Provisioning for Mainframe

Universal Volume Manager

This SOM enables or disables the performance improvement for Dynamic Provisioning volumes that are Universal Volume Manager volumes used as pool volumes.

Mode 1086 = ON (default): The performance improvement is enabled.

Mode 1086 = OFF: The performance improvement is disabled.

Notes:
  1. This SOM is applied when the IOPS performance of an external storage system is higher than 80k × the number of installed MPBs, which is the value of IOPS that an entire local storage system sends to an external storage system.
  2. When it is required to set this SOM to OFF, if IOPS sent from the local storage system to the external storage system is higher than 80k × the number of installed MPBs, reduce the IOPS to lower than 80k × the number of installed MPBs, and then set this SOM to OFF. (Otherwise CWP increases and cache is overloaded.)
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1091 TrueCopy for Mainframe

Universal Replicator for Mainframe

Compatible FlashCopy® V2

This SOM enables or disables the IBM® zHyperWrite function. When this SOM setting is changed to ON or OFF, SCI is reported to the host and the zHyperWrite function is enabled or disabled.

Mode 1091 = ON: The zHyperWrite function is enabled. (ReadFeatureCode setting for the zHyperWrite function)

Mode 1091 = OFF (default): The zHyperWrite function is disabled.

Notes:
  1. This SOM can be applied when DKCMAIN version that supports the zHyperWrite function is used.
  2. To use the zHyperWrite function, a HyperSwap environment is required.
  3. To enable the zHyperWrite function, set this SOM to ON on both MCU and RCU of TCz.
  4. To downgrade the microcode to a version that does not support the zHyperWrite function, set this SOM to OFF prior to downgrading the microcode.
  5. Even when this SOM is set to ON for a storage system in 3DC configuration, the zHyperWrite function does not work for volumes in 3DC configuration.

    However, if the mode is set to ON and the zHyperWrite + 3DC multiple-target option is enabled, the zHyperWrite function works in TCz-URz multi-target configurations.

  6. Do not set this SOM to ON if SOM 474 is set to ON.
  7. Do not set this SOM to ON if Preserve Mirror configuration is created.
  8. Do not set this SOM to ON if the TCz Function Switch 12 is set to ON.
  9. To use the zHyperWrite function, do not select Primary Volume Only as a CFW Data option at TCz pair creation.
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1093 Dynamic Provisioning

Dynamic Tiering

Thin Image

This SOM is used to disable background unmap during microcode downgrade from a version that supports pool reduction rate correction to a version that does not support the function.

Mode 1093 = ON: Background unmap cannot work.

Mode 1093 = OFF (default): Background unmap can work.

Notes:
  1. This SOM is applied when downgrading microcode from a version that supports pool reduction rate correction to a version that does not support the function is disabled.
  2. When pool capacity shrinking is performed for an FMD parity group while the mode is set to ON, the pool capacity shrinking cannot be completed. Make sure to set the mode to OFF prior to performing pool capacity shrinking for an FMD parity group.
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1096 Universal Replicator

Universal Replicator for Mainframe

When either of the following conditions (1) or (2) is met, a function that reduces the required data size and the processing frequency works for the read-journal processing. This mode is used to disable this function.
  1. There are multiple journal groups set for one MPB, and the write pending rate of a CLPR used by the journal groups is 25% or higher.

    Purpose: Rebalancing resources (such as cache) used among the journal groups in the same MPB.

    Means: Performing read-journal in the manner of round robin among journal groups to reduce the frequency of read-journal.

  2. No journal to be transferred to RCU is left on MPU.

    Purpose: Controlling the use of unnecessary resources (such as MP) used by the journal groups that leads to low load for the host.

    Means: Reducing the required data size and the processing frequency of read-journal.

Mode 1096 = ON: The read-journal frequency reduction does not work.

Mode 1096 = OFF (default): The read-journal frequency reduction works.

Notes:
  1. This SOM is applied when a significant delay, which is about 200 msec or longer, occurs in the line between MCU and RCU.
  2. When this SOM is set to ON while round-trip delay time is small (about less than 20 msec), the usage rate of RCU Initiator increases by 10% x the number of journals.
  3. Even though this SOM is supposed to be applied to UR RCU, apply it to both MCU and RCU on the premise of DR operation.
  4. This SOM is effective for each CLPR, so that select the operation target LPRxx (xx=00 to 31), and then set this SOM to ON/OFF. For example, when only CLPR0 is defined (CLPR1 to 31 are not defined), select LPR00 and then set this SOM to ON/OFF. This SOM is not effective for any CLPRs if "System" is selected even when this SOM is set to ON.
Both
1097 Common This SOM disables the warning LED to blink when specific SIMs are reported.

Mode 1097 = ON: When SIM=452XXX, 462XXX, 3077XY, 4100XX, or 410100 is reported, the warning LED does not blink.

Mode 1097 = OFF (default): When SIM=452XXX, 462XXX, 3077XY, 4100XX, or 410100 is reported, the warning LED blinks.

Note: This SOM disables the warning LED to blink when specific SIMs are reported.

-
1099 TrueCopy for Mainframe When PPRC FREEZE using GDPS works, the FREEZE turns to time-out if there are many CUs. This SOM can prevent the time-out.
Mode 1099 = ON: When FREEZE is received, the completion of path deletion for those other than the last path is not reported but only the completion of path deletion for the last path is reported. If multiple CUs share an RCU path, path deletion does not work at FREEZE per CU, so that the following phenomenon may occur:
  • After Hyperswap is performed, SSB=8BD8 and 8BD9 are logged for a pair where the Hyperswap is performed.

Mode 1099 = OFF (default): The completion of path deletion for every path is reported.

Notes:
  1. Apply this SOM when a storage system with over 32 CUs is used in a TCz environment in which PPRC FREEZE is available.
  2. To use 32 more CUs in GDPS environment, the microcode must be the supported version on both MCU and RCU and this SOM is set to ON.
MCU
1106 Dynamic Provisioning

Dynamic Provisioning for Mainframe

Dynamic Tiering

Dynamic Tiering for Mainframe

This SOM is used for either of the following:
  1. To monitor the page usage rate of parity groups defined to a pool, and perform rebalance (the same as the rebalance that works at pool expansion or after 0 data page reclamation) to balance the usage rate if the rate differs significantly among parity groups.
  2. To perform rebalance even when the number of reclaimed pages is 0 after 0 data page reclamation.
Mode 1106 = ON: The rebalance (the same as the rebalance that works at pool expansion or after 0 data page reclamation) (*3) works when one of the following conditions is met:
  1. The usage rate is checked for parity groups in a pool once a day, and the usage rate is not balanced (*1) among parity groups.
  2. After 0 data page reclamation, the number of reclaimed pages is 0 (*2).

Mode 1106 = OFF (default): The rebalance does not work even when the usage rate is not balanced.

*1: How to determine whether usage rate is unbalanced among parity groups

The pool usage rate is determined as unbalanced when there is 25% or more difference between the usage rate of each parity group in the pool and the average.

Note: For HDT pools (including those with active flash attribute), the average of parity group usage rates is calculated per tier.

Examples:
  1. In an HDP pool, if the usage rates of PG1, PG2, and PG3 are 50%, 40%, and 30% respectively, it is not determined as unbalanced.

    Because the average parity group usage rate is (50%+40%+30%) / 3 =40% and the difference in the rate between each parity group and the average is 10% at the maximum.

  2. In an HDP pool, if the usage rates of PG1, PG2, and PG3 are 80%, 40%, and 30% respectively, it is determined as unbalanced.

    Because the average parity group usage rate is (80%+40%+30%) / 3 =50% and the difference in the rate between each parity group and the average is 30% at the maximum.

  3. In an HDT pool, if the usage rates of PG1, PG2, and PG3 are 80% (SSD), 40% (SAS15K) and 30% (SAS15K), it is not determined as unbalanced, because:
    • The average parity group usage rate of Tier1 is (80%) / 1 =80% and the difference in the rate between the parity group and the average is 0%.
    • The average parity group usage rate of Tier2 is (40%+30%) / 2 =35% and the difference in the rate between the parity group and the average is 5% at the maximum.

*2: Condition for rebalance after 0 data page reclamation

When this SOM is set to ON, rebalance works even when reclaimed page is 0 at 0 data page reclamation.

*3: Rebalance (the same as the rebalance that works at pool expansion or after 0 data page reclamation) works according to the SOM1195 setting (default OFF).

Notes:
  1. This SOM is applied when balancing the usage rate is required at a customer site where the usage rate is not even.
  2. The term "page usage rate" refers to the percentage of the number of assigned pages in each PG compared to the total number of pages in the pool.

    For HDT pools, the term "total number of pages" is the number of pages assigned within each specific tier.

-
1113 Dedupe and Compression This SOM stops processing other than garbage collection and de-staging among asynchronous processing for host I/Os of those related to the capacity saving function

Mode 1113 = ON: The processing other than garbage collection and de-staging among the asynchronous processing for host I/Os of the capacity saving function is stopped.

Mode 1113 = OFF (default): The capacity saving function fully works.

Notes:

  1. The mode is applied when a failure occurs due to the asynchronous processing of the capacity saving function so that identifying a failure part, reducing the MP usage rate, and preventing the problem from further expanding are required.
  2. When this mode is set to ON, the capacity reduction processing does not work and the capacity saving rate degrades.
  3. SOM1113 is related to SOM1112. When both modes are set to ON, the setting of SOM1112 is prioritized over that of SOM1113.

    Behavior when SOM1112 is set to ON: All of asynchronous processing for host I/Os among those processing related to the capacity saving function are stopped, which means that the garbage collection and de-staging do not work, so that write I/Os to DP volumes with Compression or Deduplication and Compression set are disabled.

-
1115 Dedupe and Compression When LDEV format is performed for a virtual volume with capacity saving (Compression, or Deduplication and Compression, the same hereinafter) enabled, data is initialized without using metadata regardless of the mode setting.

Mode 1115 = ON (default): When LDEV format is performed for a virtual volume with capacity saving enabled, the data is initialized without using the metadata.

Mode 1115 = OFF: When LDEV format is performed for a virtual volume with capacity saving enabled, normal formatting is performed, but if one of the following conditions is met, the data is initialized without using metadata.
  • There is a pinned slot.
  • The capacity saving status is "Failed".
  • The virtual volume is blocked (Normal restore cannot be performed).
The processing time increases with increase in pool capacity. Estimate of processing time:
Processing time (minutes) = (pool capacity (TB)/40) + 5 

If the result of dividing the pool capacity by 40 has decimal places, round it up to the next integer.

The processing finishes early if there is less capacity of allocated pages. For example, in the case of a 4-PB pool, normal formatting (SOM 1115 OFF) is faster if the LDEV capacity is 50 GB or less, therefore the performance of LDEV format without using metadata is better.

-
1118 Open This SOM is used to disable the ENC reuse function.

Mode 1118 = ON: When a failure occurs in the Expander chip mounted on a controller board (CTLS, CTLSE) or an ENC board, the reuse function does not work but SIM=CF12XX is reported and the ENC is blocked.

Mode 1118 = OFF (default): When a failure occurs in the Expander chip mounted on a controller board (CTLS, CTLSE) or an ENC board, the reuse function works.

If the ENC is reusable, SIM=CF12XX and then CF14XX are reported, and the ENC is reused.

If the ENC is not reusable, SIM=CF12XX is reported, and the ENC is blocked.

Note: The ENC reuse function is enabled as default. This SOM is applied when you want to disable the ENC reuse function.

-
1169 Dedupe and Compression This mode can enable or disable the deduplication processing that works during resync processing from P-VOL to S-VOL by the copy function for DP-VOLs with capacity saving in Inline mode enabled.

Mode 1169 = ON (default 90-03-01 and later): Deduplication processing is not performed during resync processing.*

Mode 1169 = OFF: Deduplication processing is performed during resync processing.

* To reduce the capacity consumption in the case that the pool capacity is almost depleted for example, the deduplication processing might be performed during the resync processing. In particular, the following cases apply:
  • The usage rate exceeds the warning threshold.
  • Free capacity is smaller than about 240 GB.
Notes:
  1. When SOM 1280 is ON, deduplication processing is performed even when SOM 1169 is ON.
  2. If conditions to disable deduplication processing by SOM 1191 are met, deduplication processing is not performed even when SOM 1169 is OFF. For details about the conditions to disable deduplication processing, contact customer support (see SOM1191 sheet).
  3. When SOM 1169 is set to ON, like the post mode, estimating and reserving the capacity of a temporary storing area in the copy target DP volume or pool in advance is necessary.
  4. SOM 1169 is not effective for the initial copy at pair creation, but there are some exceptional cases for SI and VM, such as pair creation using a used volume for S-VOL. In this case, deduplication processing is performed or not performed according to the mode setting.
  5. SOM 1169 is not related to determining whether to perform deduplication processing in synchronization with initial write. For example, the setting of SOM 1169 does not contribute to a reduction in time to migrate data to a newly defined volume.
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1174 Open

Universal Volume Manager

This SOM is used to disable a path that is logged in from a host or an external storage system (host path and external path) to be used as an external path.

Mode 1174 = ON: A path logged in from a host or an external storage system is excluded from the WWN discovery target.

Mode 1174 = OFF (default):A path logged in from a host or external storage system is included in the WWN discovery target.

Notes:
  1. Apply SOM 1174 when discovery is performed while specifying a universal port that is being logged in from a host or an external storage system.
  2. If SOM 1174 is set to ON, external volumes cannot be created using the paths being logged in from hosts and external storage systems.
  3. When WWN discovery is performed while the mode is set to ON, the storage system being logged in from hosts and external storage systems are displayed as [Unknown] in the discovery result.
    Discovery works at the following operations or commands:
    • HDvM - SN: External volume addition, external path setting change
    • CCI: raidcom add external_grp, raidcom add path, raidcom discover external_storage, raidcom discover lun
  4. By specifying the -safety_check enable option for the above CCI commands, path disconnection can be prevented same as the case of setting the mode to ON. The option is supported with 90-06-01-00/00 and later and CCI 01-61-03/xx and later. For details, see Command Control Interface Command Reference.
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1175 Universal Replicator for Mainframe This SOM enables the CFW data that the P-VOL of a URz pair created fromBCM or CCI to be transferred to the S-VOL.

Mode 1175 = ON (default): The CFW data written to the URz P-VOL is transferred to the S-VOL.

Mode 1175 = OFF: The CFW data written to the URz P-VOL is not transferred to the S-VOL.

Notes:
  1. Apply the mode if the CFW data transfer from the URz P-VOL to the S-VOL is required. When a pair is created with the mode set to ON, the CFW data that the P-VOL receives is transferred to the S-VOL. It can apply to pair creation from BCM or CCI only. If a pair is created from Device Manager - Storage Navigator, whether to transfer the CFW data can be selected as usual.
  2. To transfer the CFW data to the S-VOL, a journal creation is performed as an extension of CFW write, which causes the CFW write performance to degrade compared to that when the mode is set to ON.
  3. The mode setting (ON/OFF) can be changed regardless of the URz pair status, but to transfer the CFW data to the S-VOL, a new pair must be created after setting the mode to ON.
Both
1182 Universal Replicator

Global-active device

This SOM is used to enable replacement of the journal volume on the primary storage system of the UR delta resync pair in a GAD 3DC delta resync (GAD+UR) configuration.

Mode 1182 = ON: If a reserve journal is added to the journal on the primary storage system of the delta resync pair, the status of the journal changes to HLD.

Mode 1182 = OFF (default):

Deletion of the journal whose status is HOLD, HOLDING, or HLDE is guarded on the primary storage system of the UR delta resync pair.

If a reserve journal volume has already been added, delete the reserve journal volume, and then add a reserve journal volume again while the system option mode 1182 is set to ON.

After the journal volume is replaced, restore the delta resync pair status from Device Manager - Storage Navigator (you cannot perform this operation from CCI).

MCU (MCU of delta UR pair, L site in GAD+UR config.)
1191 Dedupe and Compression This SOM is used to prevent MP usage rate from rising due to overhead of deduplication processing.

Mode 1191 = ON: Inline deduplication processing is disabled when the average of MP usages on the entire storage system is 50% or higher, or CPW is 30% or higher.

Mode 1191 = OFF (default): Inline deduplication processing is not disabled regardless of MP usage and CPW rate.

Notes:
  1. This SOM is applied when reducing impact on I/O performance is required at online data migration for a virtual volume with capacity saving enabled and the inline mode set.
  2. If this SOM is set to ON, the frequency of the asynchronous deduplication processing increases after storing the data in a temporary area so that the pool capacity decreases due to consumption of the temporary area. To use the mode therefore, decrease in pool capacity must be acceptable. In particular, verify the capacity of the temporary area in the pool by using the following conditional expressions.

    <Setting the mode at data migration>

    [Pool capacity × depletion threshold (%) / 100] is larger than [current used pool capacity + (amount of data to be migrated × (100 – estimated compression ratio (%)(*)) / 100)].

    <Setting the mode during normal operation>

    [Pool capacity × depletion threshold (%) / 100] is larger than [current used pool capacity + (amount of data to be written to area without having been written × (100 – estimated compression ratio (%)(*)) / 100)].

    * Estimated compression ratio is the ratio of the estimated compression reduction effect. To convert the compression ratio in N:1 format to percentage, use the formula: compression ratio (%) = (1 – 1 / N) × 100

  3. To set the mode to ON, first estimate temporary area in a pool and then reserve it in advance.
  4. By setting the mode to ON, the inline deduplication processing is disabled when the average MP usage is 50% or higher even though SOM 1280 is set to ON.
  5. When SOM 1169 is set to ON, the inline deduplication at copy processing is disabled regardless of SOM 1191 setting.
  6. For conditions to stop deduplication processing according to the setting combination of SOMs 1191, 1247, and 1248, contact customer support (see the SOM1191 sheet).
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1198 TrueCopy

Universal Replicator

Global-active device

This SOM enables users who do not have SVP to switch the difference management method by setting the mode to ON from CCI.

At TC, UR, or GAD pair creation or resync operation, the difference management method is switched from SM difference management to hierarchy difference management.

* The behavior when the mode is ON or OFF differs from that when user SOM #5 or #6 is set to ON or OFF.

Mode 1198 = ON: The difference management method for volumes of 4 TB or less used in TC, UR, or GAD pairs is changed to hierarchical difference management regardless of SOM 5, SOM 6, and SOM 1199 settings.

Mode 1198 = OFF (default):
  • When SOM 1198 is OFF and SOM 1199 is ON, the difference management method for volumes of 4 TB or less used in TC, UR, or GAD pairs is changed to SM difference management.
  • When both SOM 1198 and SOM 1199 are OFF, the difference management method is not changed.
Notes:
  1. Changing the difference management method can affect the I/O response performance depending on the I/O pattern.
  2. Changing the difference management method can affect the initial copy time depending on the conditions.
Both
1199 TrueCopy

Universal Replicator

Global-active device

This mode is used to enable changing the difference management method from hierarchical difference management back to SM difference management if necessary for some reasons after the method was changed to hierarchical difference management by setting SOM 1198 to ON. The difference management method is changed at the first TC, UR, or GAD pair creation or resync operation after setting this mode.

The behavior of this SOM differs depending on the settings of SOM #5 or #6.

Mode 1199 = ON:
  • When both SOM 1199 and SOM 1198 are ON, the difference management method for volumes of 4 TB or less used in TC, UR, or GAD pairs is changed to hierarchical difference management regardless of SOM 5 and 6 settings.
  • When SOM 1199 is ON and SOM 1198 is OFF, the difference management method for volumes of 4 TB or less used in TC, UR, or GAD pairs is changed to SM difference management regardless of SOM 5 and 6 settings.
Mode 1199 = OFF (default):
  • When SOM 1199 is OFF and SOM 1198 is ON, the difference management method for volumes of 4 TB or less used in TC, UR, or GAD pairs is changed to hierarchical difference management regardless of SOM 5 and 6 settings.
  • When both SOM 1199 and SOM 1198 are OFF, the difference management method is not changed.
Notes:
  1. The SOM is applied to enable users who use CCI in TC, UR, and GAD operations to switch difference management method from hierarchy difference management to SM difference management for volumes of 4TB or less used in TC/UR/GAD pairs.
  2. Changing the difference management method can affect the I/O response performance depending on the I/O pattern.
  3. Changing the difference management method can affect the initial copy time depending on the conditions.
Both
1201 Global-active device This SOM is used to change the I/O mode to Local for the volumes in the storage system opposite to the one where a failure occurs.

You need to set this mode on both the primary and secondary storage systems.

Mode 1201 = ON: When a path failure occurs between a quorum disk and a storage system, and then a path failure occurs between storage systems, the I/O mode of volumes of the storage system opposite to the one with path failures changes to Local.

Mode 1201 = OFF (default): When a path failure occurs between a quorum disk and a storage system, and then a path failure occurs between storage systems, the I/O mode of the P-VOL changes to Local.

Setting this SOM to ON means that the SOM must be ON on both sides. If the SOM is OFF on either side, the behavior is the same as when the mode is set to OFF.

Even when this SOM is set to ON, the I/O mode of a volume of the other storage system does not always change to Local. (This SOM is effective in the case that the I/O mode of the P-VOL is Local while the mode is set to OFF.)

Note: Apply this SOM when keeping the volumes of a storage system with no path failure between a quorum disk and the storage system accessible from hosts is required when a path failure occurs between storage systems after the path failure between a quorum disk and the other storage system.

Both
1202 Common This mode can be used to disable the logic of response performance improvement for host I/O during FMD or SSD drive firmware replacement.
Mode 1202 = ON:
  • Synchronous read I/Os are disabled.
  • Read I/Os other than synchronous read are disabled.
  • Write I/Os are disabled.
Mode 1202 = OFF (default):
  • Synchronous read I/Os can be done by collection read.
  • Read I/Os other than synchronous read are disabled.
  • Write: I/Os are disabled.
Notes:
  1. Apply this mode when changing the behavior back to the previous one is required during FMD and SSD firmware replacement.
  2. When this mode is set to ON, the host I/O performance during FMD or SSD drive firmware replacement may be degraded.
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1204 Dynamic Provisioning

Dynamic Provisioning for Mainframe

Dynamic Tiering

Dynamic Tiering for Mainframe

Thin Image

This SOM is intended to improve the page migration performance when the MP usage rate is within the range from 30% to 50%.

Mode 1204 = ON: When the MP usage rate is within the range 30 to 50%, the processing interval is shortened to improve the page migration throughput.

Mode 1204 = OFF (default): There is no change for the processing interval.

For details, contact customer support (see SOM1204 sheet).

Notes:

  1. Apply this mode when the following conditions are met:
    • The MP usage rate constantly exceeds 30%.
    • Prioritizing the page migration processing over the I/O processing is required.
  2. When SOM 1204 is set to ON, the operation frequency of the relocation processing increases so that the host I/O response performance is degraded.
  3. When SOM 904 is set to ON, the SOM 904 setting is prioritized.
  4. By setting SOM 1204 to ON, the MP usage rate increases by 3 to 10% due to the asynchronous processing, and the host I/O response may be degraded.
-
1205

Dynamic Provisioning

Dynamic Tiering

Thin Image

This SOM changes the background unmap processing speed.

Mode 1205 = ON: Background unmap runs at up to 42 MB/s.

Mode 1205 = OFF (default): Background unmap runs at up to 10 GB/s.

Notes:
  1. The mode is applied to prevent the host response performance from being degraded due to background unmap.
  2. When SOM 1122 is set to ON, the SOM 1122 setting is prioritized.
  3. As releasing physical areas runs at the normal speed, the following phenomena may occur, though the phenomena are solved immediately after the physical area release is complete:
    • The used pool capacity does not decrease immediately after DP volume deletion.
    • The saving ratio seems to be lower temporarily.
    • The used pool capacity may increase due to rebalance.
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1211 Universal Replicator

Universal Replicator for Mainframe

By setting this SOM to ON, the threshold of write pending rate that is a condition to disable journal data copy is changed from 25% to 50%.
Journal data copy is disabled when the following conditions (1) and (2), or (1) and (3) are met:
  1. 4096 or more journal data sets are accumulated on RCU.
  2. The write pending rate of a journal volume in an MPB that has the ownership of the journal on RCU exceeds the threshold, 25% (mode OFF) or 50% (mode ON). (Including the write pending rate of those other than the journal volume)
  3. On RCU, it takes 15 seconds or longer to start a restore operation after the copy processing of journals is complete.

Note: Even when the above conditions are met, if the time stamp of accumulated journal datasets is the same in a configuration where multiple journals are added to a consistency group, journal data copy is not disabled.

Mode 1211 = ON: The threshold for the write pending rate is 50%.

Mode 1211 = OFF (default): The threshold for the write pending rate is 25%.

Notes:
  1. Apply this SOM when one of the following conditions are met:
    1. Disabling journal data copy is enabled in one of the following cases:

      - SOM 1043 is set to ON for each CLPR on the secondary site.

      - A configuration where multiple journals are added to a CCI consistency group (open and mainframe).

      - A configuration where multiple journals are added to an extended consistency group (mainframe).

    2. The write pending rate of a CLPR containing a journal on the secondary site exceeds 25%.
  2. If the host write I/O speed is faster than the journal data copy speed, the usage of the master journal increases.
  3. Though the mode can work on UR/URz RCU, apply it to both MCU and RCU assuming Disaster Recovery operation.
  4. This mode is related to SOM 1043.
  5. If SOM 690 is set to ON and the write pending rate is 60% or higher, journal data copy is disabled regardless of the setting of this mode.
  6. This mode is effective per CLPR. Therefore, select a target LPR xx (xx= 00 to 31), and then set the mode to ON or OFF. For example, when setting the mode to CLPR0 (CLPR 1 to 31 are not defined), select LPR00, and then set the mode to ON or OFF. When setting the mode by selecting System, the mode cannot be enabled for any CLPRs.
Both
1222 Dynamic Tiering

Dedupe and Compression

This SOM changes whether to perform the gray zone promotion processing on compressed pages.

Mode 1222 = ON: The gray zone promotion processing is performed on compressed pages.

Mode 1222 = OFF (default): The gray zone promotion processing is not performed on compressed pages.

Notes:

  1. Apply this SOM to prioritize the performance over reduction ratio.

    In an ADR with HDT environment, if the usage rate of the second lowest tier is lower than the upper limit of the setting value, the usage rate can be increased by setting this mode to ON.

  2. When this SOM is set to ON, the reduction ratio declines by the gray zone promotion processing, and then the pool usage increases.
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1223 Dynamic Provisioning This SOM is used to disable the mapping consistency check processing that runs when a Write Same command is run.

Mode 1223 = ON: The mapping consistency check processing does not run at Write Same command.

Mode 1223 = OFF (default): The mapping consistency check processing runs at Write Same command.

Note: Apply this SOM when all the following conditions are met:

  1. The microcode that supports the mode is applied.(90-04-08 and later in 90-04-0x range, 90-05-03 and later)
  2. The response time of Write Same command increase about 0.1 msec.
  3. The length of Write Same command is short (less than 256KiB).
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1224 ShadowImage

ShadowImage for Mainframe

Thin Image

Volume Migration

Universal Replicator

Universal Replicator for Mainframe

The mode can disable or enable ownership migration for an LDEV whose ownership has been migrated to the MPU with P-VOL ownership at pair creation back to the previous MPU at pair deletion.

Mode 1224 = ON: Ownership migration at program product pair deletion is disabled.

Mode 1224 = OFF (default): Ownership migration at program product pair deletion is performed.

* Different from other program products, the ownership in an MPU with the journal group ownership is migrated as follows in a UR/URz configuration.
  • Ownership migration target: LDEV (journal volume, remote CMDDEV)
  • Timing when ownership migration takes place: Journal volume deletion, journal group deletion from EXCTG, and mirror allocation release
Notes:
  1. Apply the mode when preventing the MP usage rate increase is required.
  2. Ownerships are in a specific MPU so that I/Os may be concentrated on the MPU.
  3. Ownership migration does not work at pair deletion.
Both
1242 Universal Replicator

Universal Replicator for Mainframe

By setting this SOM to ON on a storage system with a pair for delta resync in one of the following configurations, SIM=DCF6XX (XX=JNLG number) is reported as a warning for an omission of remote command device settings for delta resync. The SIM is reported once 24 hours after the pair for delta resync is created in the target journal group.

[Target configuration]

(a) UR or URz

(b) TC/TCz-UR/URz delta resync configuration or a UR/URz-UR/URz

Mode 1242 = ON: SIM=DCF6XX is reported regularly if a remote command device for delta resync was not added in the target configuration. The SIM is reported for each journal group to which a remote command device for delta resync was not added.

Mode 1242 = OFF (default): SIM=DCF6XX is not reported.

Note: This SOM can be applied when users want to receive a warning report for an omission of remote command device settings for delta resync.

Both
1254 ShadowImage

ShadowImage for Mainframe

Volume Migration

Compatible FlashCopy®

TrueCopy

TrueCopy for Mainframe

Global-active device

Universal Replicator

Universal Replicator for Mainframe

This mode is used to prevent the performance of a host I/O to a virtual volume with capacity saving enabled (DRD-VOL) from being degraded due to the copy processing of a replication program product* that runs in the background.

* Replication program products: ShadowImage (SI), ShadowImage for Mainframe (SIz), Volume Migration (VM), FlashCopy (FC), Thin Image (HTI), TrueCopy (TC), TrueCopy for Mainframe (TCz), global-active device (GAD), Universal Replicator (UR), Universal Replicator for Mainframe (URz).

Mode 1254 = ON:
  • SI/SIz, VM, HTI, TC/TCz, GAD, UR/URz: The copy processing running in the background* stops when the WP rate of the copy target CLPR is 35% or higher.
  • FC: The pace of the copy processing running in the background* is slowed down when the WP rate of the copy target CLPR is 35% or higher.
Mode 1254 = OFF (default):
  • SI/SIz, VM, FC, TI: As per the SOM 467 setting
  • TC/TCz, GAD: As per the SOM 689 setting
  • UR/URz: As per the SOM 690 setting

* The copy processing running in the background refers to the following processing:

  • SI/SIz: Pair initial copy, pair initial copy (Steady Split), pair initial copy (Quick Split), Steady Split, Quick Split (it does not stop for a pair whose synchronization rate is 100%), Normal Resync (it does not stop for a pair whose synchronization rate is 100%), Reverse Copy (it does not stop for a pair whose synchronization rate is 100%), background copy.
  • VM: Pair initial copy
  • FC: Background copy, update co+F96py (Restore), update copy (Reverse Restore), update copy (Fast Reverse Restore)
  • TI: Copy processing by restore, copy processing by clone
  • TC/TCz: Copy running in background, initial copy, pair creation, resync, swap resync, horctakeover (swap resync run during horctakeover)
  • GAD: Initial copy, pair creation, resync, swap resync, horctakeover (swap resync run during horctakeover)
  • UR: Copy or restore running in background, initial copy, update copy, journal copy (initial and update copy), journal restore, issuing read-journal command to primary storage system, data copy from master journal to restore journal, copying restore journal data for secondary volume, pair creation, resync, swap resync, delta resync, horctakeover (swap resync run during horctakeover)
Notes:
  1. Apply this mode when all the following conditions are met:
    1. Preventing the performance of a host write I/O to a DRD-VOL from being degraded due to overload by the copy processing running in the background is required.
    2. It is acceptable that completing the copy processing running in the background for a volume (*1) belonging to a CLPR whose WP rate is 35% or higher takes extra time equal to the time period during which the WP rate of the copy target CLPR is 35% or higher.
    3. Setting the mode for all CLPRs on the storage system is required. (For per CLPR setting, use SOM 1260.)
    4. A failure suspension of a UR/URz pair is acceptable (*2)(*3). The failure suspension occurs when the mode is set to ON to prioritize the host I/O performance in a UR/URz configuration, if the amount of host I/Os exceeds the amount of journal transfer so that the journal usage increases, and then the journal usage exceeds the threshold.

    *1: Note that in CLPRs with the mode set to ON, the copy processing does not make progress for not only a DRD-VOL but also a normal volume and a virtual volume with capacity saving disabled.

    *2: Disable Inflow Control for journals. By setting SOM 1254, the copy processing running in the background is stopped, the amount of host I/Os exceeds the amount of journal transfer, and the journal usage increases. If Inflow Control is enabled, failure suspension can be prevented, but Inflow Control works when the journal usage exceeds the threshold (80%), resulting in host write performance degradation.

    *3: If a failure suspension is not acceptable, use different CLPRs for the UR/URz S-VOL and JNL VOL, and for the DRD-VOL whose performance cannot be degraded on RCU, and then set SOM 1260 to ON only f+F97or the CLPR of the DRD-VOL whose performance cannot be degraded.

  2. By setting the mode to ON, the copy processing running in the background is stopped when the WP rate is 35% or higher regardless of the settings of SOM 467, SOM 689, and SOM 690.
  3. Completing the copy processing running in the background for a volume (*4) belonging to a CLPR whose WP rate is 35% or higher takes extra time equal to the time period during which the WP rate of the copy target CLPR is 35% or higher. Note that recovering a pair that is suspended due to failure takes longer time too. SOM 1254 cannot be applied if the copy processing, such as the case of data migration or volume migration, must be completed in a certain time period.

    *4: Note that in CLPRs with the mode set to ON, the copy processing does not make progress for not only a DRD-VOL but also normal volume and virtual volume with capacity saving disabled.

  4. When UR/URz is used, if 35% or higher WP rate continues for a long time on RCU, a journal volume becomes full and may be suspended on MCU.

    To disable the copy running in the background of replication program products other than UR/URz, do not set the mode to ON.

    Instead of setting the mode to ON, use different CLPRs for the UR/URz S-VOL and the journal volume, and for the DRD-VOL for which preventing performance degradation is required on RCU, and set SOM 1260 to ON for the CLPR of the DRD-VOL only.

  5. In a 3DC configuration, if 35% or higher WP rate continues for a long time on the second RCU, a journal volume becomes full and may be suspended on MCU and the first RCU. In this case, even if you perform delta resync, all data copy from P-VOL to S-VOL works same as the case when delta resync fails.
  6. In a UR M:N open CTG configuration, even if there is one storage system where the WP rate reaches 35% or higher on RCU, copy processing will be stopped on all storage systems in this configuration, including the storage systems with SOM 1254 disabled.
  7. In a URz EXCTG configuration, even if there is one storage system where the WP rate reaches 35% or higher on RCU, copy processing will be stopped on all storage systems in this EXCTG, including the storage systems with SOM 1254 disabled.
  8. Apply the same setting of SOM1260 for the CLPR of UR/URz S-VOL and the CLPR of the journal volume.

    (Set the mode to ON or OFF for both CLPRs)

  9. When UR/URz is used, if operations are switched to RCU, as the previous MCU becomes RCU, meet the following conditions:
    1. The SOM setting is same for MCU and RCU.
    2. If different CLPRs are used for the UR/URz S-VOL and the journal volume, and for a DRD-VOL for which preventing performance degradation is required on RCU, use different CLPRs for the UR/URz S-VOL and the journal volume, and for a DRD-VOL for which preventing performance degradation is required on MCU too.
  10. In a 3DC configuration, because operations on MCU can be switched to the first RCU or the second RCU, make sure the SOM setting is the same on the MCU, the first RCU and the second RCU.
  11. When UR/URz is used, disable Inflow Control. If enabled, it may work because the copy is stopped by setting the mode to ON, resulting in degradation of host write I/O performance.

*1: In CLPRs with the mode set to ON, the copy processing does not make progress for not only a DRD-VOL but also a normal volume and a virtual volume with capacity saving disabled.

*2: Disable Inflow Control for journals. By setting SOM 1254, the background copy is stopped, the amount of host I/Os exceeds the amount of journal transfer, and the journal usage increases. If Inflow Control is enabled, failure suspension can be prevented, but Inflow Control works when the journal usage exceeds the threshold (80%), resulting in host write performance degradation.

*3: Note that in CLPRs with the mode set to ON, the copy processing does not make progress for not only a DRD-VOL but also normal volume and virtual volume with capacity saving disabled.

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1259 Common This SOM is used to enable and disable DIMM hardware diagnosis processing during controller startup.

This mode can be set only on VSP 5200, 5600, 5200H, 5600H models.

Mode 1259 = ON: The DIMM hardware diagnosis processing does not run at controller startup.

Mode 1259 = OFF (default): The DIMM hardware diagnosis processing runs at controller startup.

Notes:

  1. Apply this mode to reduce the PS ON time when a quicker startup time is required. The time to complete PS ON and controller maintenance operation becomes 5 minutes shorter.
  2. By setting the mode to ON, the time to complete PS ON and controller maintenance operation becomes 5 minutes shorter.
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1260 Dedupe and Compression

ShadowImage

ShadowImage for Mainframe

Volume Migration

Compatible FlashCopy®

TrueCopy

TrueCopy for Mainframe

Global-active device

Universal Replicator

Universal Replicator for Mainframe

This mode is used to prevent the performance of a host I/O to a virtual volume with capacity saving enabled (DRD-VOL) in the specified CLPR from being degraded due to the copy processing of a replication program product (*) that runs on the background.

*: ShadowImage (SI), ShadowImage for Mainframe (SIz), Volume Migration (VM), Compatible FlashCopy® (FC), Thin Image (TI), TrueCopy (TC), TrueCopy for Mainframe (TCz), global-active device (GAD), Universal Replicator (UR), Universal Replicator for Mainframe (URz).

Mode 1260 = ON:

SI/SIz, VM, TI, TC/TCz, GAD, UR/URz: The copy processing running in the background* stops when the WP rate of the copy target CLPR is 35% or higher.

FC: The pace of the copy processing running in the background* is slowed down when the WP rate of the copy target CLPR is 35% or higher.

* The copy processing running in the background refers to the following processing:

  • SI/SIz: Pair initial copy, pair initial copy (Steady Split), pair initial copy (Quick Split), Steady Split, Quick Split (it does not stop for a pair whose synchronization rate is 100%), Normal Resync (it does not stop for a pair whose synchronization rate is 100%), Reverse Copy (it does not stop for a pair whose synchronization rate is 100%), background copy.
  • VM: Pair initial copy
  • FC: Background copy, update co+F96py (Restore), update copy (Reverse Restore), update copy (Fast Reverse Restore)
  • TI: Copy processing by restore, copy processing by clone
  • TC/TCz: Copy running in background, initial copy, pair creation, resync, swap resync, horctakeover (swap resync run during horctakeover)
  • GAD: Initial copy, pair creation, resync, swap resync, horctakeover (swap resync run during horctakeover)
  • UR: Copy or restore running in background, initial copy, update copy, journal copy (initial and update copy), journal restore, issuing read-journal command to primary storage system, data copy from master journal to restore journal, copying restore journal data for secondary volume, pair creation, resync, swap resync, delta resync, horctakeover (swap resync run during horctakeover).

Mode 1260 = OFF (default):

SI/SIz, VM, FC, TI: As per the SOM 467 setting

TC/TCz, GAD: As per the SOM 689 setting

UR/URz: As per the SOM 690 setting

Notes:
  1. Apply the mode when all the following conditions are met.
    • Preventing the performance of a host write I/O to a DRD-VOL from being degraded due to overload by the background copy processing is required.
    • It is acceptable that completing the background copy for a volume (*1) belonging to a CLPR whose WP rate is 35% or higher takes extra time equal to the time period during which the WP rate of the copy target CLPR is 35% or higher.
    • Setting the mode per CLPR is required. (Setting for all CLPRs, use SOM 1254)
    • The mode setting for a CLPR of UR/URz S/VOL, and that for a CLPR of a journal volume are the same. (The mode is set to ON or OFF for both CLPRs)
    • *1: Note that in CLPRs with the mode set to ON, the copy processing does not make progress for not only a DRD-VOL but also a normal volume and a virtual volume with capacity saving disabled.
  2. By setting the mode to ON, the copy processing running in the background is stopped when the WP rate is 35% or higher regardless of the settings of SOM 467, SOM 689, and SOM 690.
  3. Completing the copy processing running in the background for a volume (*2) belonging to a CLPR whose WP rate is 35% or higher takes extra time equal to the time period during which the WP rate of the copy target CLPR is 35%. Note that recovering a pair that is suspended due to failure takes longer time too.

    *2: Note that in CLPRs with the mode set to ON, the copy processing does not make progress for not only a DRD-VOL but also normal volume and virtual volume with capacity saving disabled.

  4. When UR/URz is used, if 35% or higher WP rate continues for a long time on RCU, a journal volume becomes full and may be suspended on MCU.

    To disable the background copy of replication program products other than UR/URz, use different CLPRs for the UR/URz S-VOL and the journal volume, and for a DRD-VOL for which preventing performance degradation is required on RCU, and set the mode to ON for the CLPR of the DRD-VOL only.

  5. When UR/URz is used, if operations are switched to RCU, as the previous MCU becomes RCU, meet the following conditions:
    • The SOM setting is same for MCU and RCU.
    • If different CLPRs are used for theUR/URz S-VOL and the journal volume, and for a DRD-VOL for which preventing performance degradation is required on RCU, use different CLPRs for the UR/URz S-VOL and the journal volume, and for a DRD-VOL for which preventing performance degradation is required on MCU too.
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1267 Dedupe and Compression When asynchronous processing of capacity saving runs while the drive performance is not sufficient, the asynchronous processing raises the workload of the drive. As the drive is overloaded, the drive performance may be degraded. To address the issue, this mode is available to slow down the asynchronous processing speed.

Mode 1267 = ON: The asynchronous processing of capacity saving listed below runs at low speed.

Mode 1267 = OFF (default): The asynchronous processing of capacity saving listed below runs at normal speed.

Asynchronous processing that runs at low speed by setting the mode to ON:
  • Disabling of the capacity saving function
  • Deletion of LDEVs for which the capacity saving function is enabled
  • Garbage collection
  • Asynchronous capacity reduction processing
  • Compression conversion of compression accelerator
  • Garbage collection for collecting unnecessary meta data or user data of deduplication system data volume (data store)
  • Deletion of unnecessary hash data for deduplication
  • Expansion of meta data area of the capacity saving
  • Correction of control information when SOM 1208 is set to ON
  • Health check when SOM 1237 is set to ON
Notes:
  1. Apply this mode in the following cases:
    • There is a possibility of drive overload by the asynchronous processing (asynchronous capacity reduction, disabling capacity saving, compression conversion of compression accelerator) that works after the data reduction setting (capacity saving, compression accelerator) is changed.
    • The drive is overloaded by asynchronous processing of capacity saving.
  2. By setting the mode to ON, the capacity saving ratio may decrease.
  3. When an adaptive data reduction setting change is complete after setting the mode to ON, set the mode to OFF.
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1273 Universal Replicator for Mainframe This SOM is used to prevent recovery point objective (RPO) from increasing due to many format write I/Os in a URz configuration.

Mode 1273 = ON: The number of journal restore operations on RCU is as follows:

  • Multiplicity per MPU: 256
  • Multiplicity per 32-cylinder range: 8

Mode 1273 = OFF (default): The number of journal restore operations on RCU is as follows:

  • Multiplicity per MPU: 256
  • Multiplicity per 32-cylinder range: 256

Notes:

  1. Apply the mode when the following conditions are met.
    • The amount of journal transfer for each MPU on RCU is 500 MB/s or greater.
    • The ratio of format write I/Os is 50% or higher.
    • There is no other bottleneck (MP usage rate, write pending rate, and drive operating rate).
  2. When a cylinder range that a new write I/O accesses is narrow and the number of pairs to which I/Os are issued is less than 32, the maximum performance of the journal processing on RCU may be 15 to 25% lower than that when the SOM is not set.
RCU
1293 Global-active device This SOM is used to enable the pair creation, resynchronization, and swap resynchronization operations for GAD pairs when one side of the cache is blocked.

Mode 1293 = ON: This setting allows the pair creation, resynchronization, and swap resynchronization operations for GAD pairs.

Mode 1293 = OFF (default): With this setting, the pair creation, resynchronization, and swap resynchronization operations for GAD pairs are not possible.

Notes:

  1. When this mode is ON, if the initial copy of a GAD pair runs while one side of the cache is blocked, the following adverse effects might occur:
    • The load on the drives increases, which might affect host performance.
    • The initial copy performance is degraded compared to when the cache is in normal state.
    • Maintenance of the blocked cache is unavailable during the initial copy.

    During the initial copy, if degradation of host performance is unacceptable or if you perform maintenance of the blocked cache, stop the initial copy.

  2. This mode is available for DKCMAIN microcode versions 90-08-81 and later.
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1294 TrueCopy for Mainframe This SOM is used to downgrade the microcode.

Mode 1294 = ON: Downgrading the microcode from a version that supports the differential data copy function (90-09-21 or later) to a version that does not support the differential data copy function (90-09-1x or earlier) in a PPRC multi-target configuration is enabled.

To downgrade the microcode to the unsupported version, first delete TrueCopy for Mainframe pairs created with the supported version in the PPRC multi-target configuration, and then set SOM 1294 to ON. After downgrading the microcode to the unsupported version is complete, set SOM 1294 back to OFF.

Mode 1294 = OFF (default): Downgrading the microcode from a version that supports the differential data copy function (90-09-21 or later) to a version that does not support the differential data copy function (90-09-1x or earlier) in a PPRC multi-target configuration is disabled.

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