System option modes for VSP One Block

The following table lists and describes the SOMs for the VSP One Block storage systems. 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
20	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
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 turns to time-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 the SOM to ON, the port is blocked when the number of failures reaches the half point 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 the 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: Basically, setting the SOM to ON is required. The SOM can be set to OFF only in a case that the customer does not allow to set the SOM to ON for a storage system already in production. Settings of SOM 363, SOM 365, and SOM 809 are related to 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).	-
164	Global-active device	About writing data from a host if one of the controller boards fails. A controller board might fail due to unavailability of redundant cache memory because of an error in a controller board or cache memory. If this happens, SOM 164 lets you change the type of operation to accommodate each user’s needs regarding writing of data from a host. Mode 164 = ON: The write-after operation is performed. When a host writes data while one of the controller boards is inactive due to a failure, the host is notified of the completion of data write when data is written to cache memory. The degradation of write performance of a single controller board in operation is reduced. However, if the active controller board also fails, the write pending data in that controller board is lost. If your system requires high data reliability like RAID, system-wide data redundancy measures are required. Mode 164 = OFF (default): The write-through operation is performed. When a host writes data while one of the controller boards is inactive due to a failure, the host is notified of the completion of data write when data is written to a disk drive. If the active controller board also fails, the write pending data in that controller board is not lost. However, write performance is compromised while only one of the controller boards is active. If you decide to set SOM 164 to OFF, you need to design a system that can tolerate degradation of performance such as I/O response.	Both
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 is 8 seconds. Notes: This SOM applies to a site where strict host response performance is required. If a hardware failure occurs when this SOM is set to ON, the time until MPB blockage is determined is shorter than usual.	-
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, this SOM can minimize the impact on other uses. Mode 454 = OFF (default): The amount of the entire destage processing is periodically determined by using the highest workload of all CLPRs (). (The larger the workload is, the larger the amount of the entire destage processing becomes.) (write pending capacity of CLPR#x of concerned MPB) / (cache capacity of CLPR#x of concerned MPB), where x=0 to 31 and 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 Mode 454 to OFF in most cases.	-
459	ShadowImage ShadowImage for Mainframe Universal Volume Manager	By setting this SOM to ON while an external volume is used as an SI S-VOL, a function to complete destaging the S-VOL data to the external volume mapped to the S-VOL before the SI pair status changes to PSUS works. The pair status changes to PSUS when the destaging is complete. When a split operation is performed for an SI 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 destaging 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 destaging to be complete. Notes: Apply the SOM 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. The function works for the pairs created while the SOM is set to ON and does not work for the pairs created while the SOM is set to OFF. 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. When both SOM 459 and SOM 1263 are used, the throughput improvement by setting SOM 1263 to ON cannot be expected. At a split operation, the time required to change the status to PSUS when the SOM is ON gets longer than that when the SOM is set to OFF.	-
467	Cross-OS File Exchange FlashCopy^® V2 ShadowImage ShadowImage for Mainframe Thin Image Advanced Volume Migration	The current copy processing slows down if the dirty percentage is 60% or larger, and it stops if the dirty percentage is 75% or larger. SOM 467 prevents the dirty percentage from over 60% so that the host performance is not affected. Mode 467 = ON (default): The copy processing stops if the dirty percentage is 60% or larger. If the dirty percentage becomes lower than 60%, the copy processing restarts. Mode 467 = OFF: The copy processing slows down if the dirty percentage is 60% or larger, and it stops if the dirty percentage is 75% or larger. Notes: This SOM must always be set to ON when using an external volume as the secondary volume of any of the applicable replication products. It takes longer to finish the copy processing because it stops for prioritizing the host I/O performance. 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. Check the write pending rate of each volume 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 FlashCopy^® V2, SI, SIz, or VM pairs belong exceeds the threshold, the copy operation is stopped.	-
471	Thin Image	Since the SIM-RCs generated when the usage rate of a Thin Image pool 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 the 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.	-
474	Universal Replicator Universal Replicator for Mainframe	UR/URz initial copy performance can be improved by issuing a command from CCI or BCM to execute a dedicated script consisting of UR/URz initial copy (Nocopy), UR/URz suspend, TC/TCz initial copy, TC/TCz delete, and UR/URz resync. Mode 474 = ON: For a suspended UR/URz pair, a TC/TCz (Sync) pair can be created with the same P-VOL/S-VOL so that UR/URz initial copy time can be reduced by using the dedicated script. Mode 474 = OFF (default): For a suspended UR/URz pair, a TC/TCz (Sync) pair cannot be created with the same P-VOL/S-VOL. For this, the dedicated script cannot be used.	Both
484	TrueCopy for Mainframe	This SOM allows you to select a method of displaying the status of remote copy paths by using the PPRC CQUERY command. Mode 484 = ON: Displays the path as a Fibre Channel interface using a WWNN. Mode 484 = OFF: Displays the path as a conventional ESCON(R) interface. WWNNs are disabled.
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/URz 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
624	Universal Replicator Universal Replicator for Mainframe	The SOM can be set to ON for storage systems in a CCI consistency group. Mode 624 = ON: If 5 minutes have passed after time stamp update from CCI stops (), pairs of journal groups on the storage systems with the SOM 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): Pair are not suspended due to failure 5 minutes after time stamp update from CCI stops. Notes: Apply the 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. When the 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. To stop a CCI instance for 5 minutes or longer for CCI configuration definition file rewriting or server maintenance, set the SOM to OFF. If the DKCMAIN microcode is downgraded to an unsupported version while the SOM is set to ON, and then the microcode is to be upgraded to the supported version, set the SOM to OFF before the microcode upgrade.	MCU
689	Global-active device TrueCopy TrueCopy for Mainframe	This SOM is used to slow the initial copy and resync operations when the write-pending rate on the RCU exceeds 60%. Mode 689 = ON (default): The initial copy and resync copy operations are slowed down when the Write Pending rate on RCU exceeds 60%. If the 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: 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: This SOM can be set online. The micro-programs on both MCU and RCU must support this SOM. This SOM should be set when requested by the user. 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. If the write-pending status remains at 60% or higher on the RCU for a long time, it takes extra time for the initial copy and resync copy to be completed due to the slower copy operations. 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. As the SOM is enabled per DKC, in an environment where TC and GAD are used, the SOM is applied to both program products. When GAD is installed in a storage system that already uses TC, TC initial copy might take longer time.	Both
690	Universal Replicator Universal Replicator for Mainframe	This SOM is used to prevent copy processing or restore processing when the Write Pending rate exceeds 60% as follows: When the Write Pending rate of the MP unit with the journal volumes for the secondary storage system exceeds 60%, copy processing is prevented. When the Write Pending rate of the MP unit with the S-VOL exceeds 60%, restore processing is prevented. Mode 690 = ON: Copy processing or restore processing is prevented when the Write Pending rate of the MP unit for the secondary site exceeds 60%. Mode 690 = OFF (default): Copy processing or restore processing is not prevented when the Write Pending rate exceeds 60% (the same as before). Notes: This SOM can be set online. This SOM should be set per customer’s requests. If the Write Pending status long keeps 60% or more, it takes extra time for the initial copy to be completed by making up for the prevented copy operation. If the Write Pending status long keeps 60% or more, the pair status may become Suspend due to the JNL-Vol being full.	RCU
704	FlashCopy^® ShadowImage ShadowImage for Mainframe Volume Migration	To reduce the chance of MIH, this SOM can reduce the priority of SI, SIz, FlashCopy^®, 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: 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. 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.	-
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. For the device of Not Ready blockade, the Device Health Check is executed after 30 seconds. Mode 725 = OFF (default): When Not Ready is returned three times in three minutes, the path is blocked and the path status cannot be automatically recovered (Response error blockade). Notes: Applying this SOM is recommended when SUN storage is used as an external storage. Applying this SOM is recommended if 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.	-
734	Dynamic Provisioning Dynamic Provisioning for Mainframe	When exceeding the pool threshold, the SIM is reported as follows: Mode 734 = ON (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. If the pool usage rate continues to exceed both of the warning threshold and the depletion threshold, SIM-RC625000 or 62B000 is repeatedly reported every eight (8) hours until the pool usage rate falls below the depletion threshold. Mode 734 = OFF: 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 both of the warning threshold and the depletion threshold. Notes: This SOM is turned ON to prevent the Write I/O operation from being unavailable due to pool full. If the pool threshold exceeding SIM occurs frequently, other SIMs may not be reported. 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. Turning on SOM 741 can provide the SIM report to not only the users but also the service personnel. SIM=625000 or 62B000 is reported every 8 hours.	-
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) SIM-RC 625000 (DP pool usage rate continues to exceed the threshold). Mode 741 = ON: SIM is reported to service personnel. Mode 741 = OFF (default): SIM is not reported to service personnel. Notes: 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. When SOM 734 is turned OFF, SIM-RC625000 is not reported to the service personnel even though this SOM is ON.	-
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: This SOM is applied when the EMC SYMMETRIX is connected using UVM. 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. 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.	-
749	Dynamic Provisioning Dynamic Provisioning for Mainframe	This SOM disables the DP Rebalance function which allows the drives of all ECC Groups in the pool to share the load. Mode 749 = ON: The DP Rebalance function is disabled. Mode 749 = OFF (default): The DP Rebalance function is enabled. Notes: This SOM is applied when no change in performance characteristic is desired. When a pool is newly installed, the load may be concentrated on the installed pool volumes. When 0 data discarding is executed, load may be unbalanced among pool volumes. Pool-VOL deletion while this SOM is set to ON fails. To delete pool-VOLs, set this SOM to OFF.	-
757	Common	Disables or enables outputting 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: SOM 757 applies to the sites where outputting the In-band audit logs is not needed. 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. If outputting the in-band audit log is desired, set this SOM to OFF.	-
784	Global-active device TrueCopy TrueCopy for Mainframe	This SOM can reduce the time-out (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 time-out occurrence in the environment where host time-out time is short (15 seconds or less). This SOM is applied at pair creation or resync operation for each TC, TCz, or GAD pair if this SOM is set to ON on both the primary and secondary sites. (Not effective by just setting this SOM to ON.) This SOM is applied to TC, TCz, and GAD. This SOM supports paths between DKCs using Fibre, but not those between DKCs using iSCSI. Mode 784 = ON (default): 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. In addition, if data copy is delayed 5 seconds at creation or resynchronization of a TC, TCz, or GAD pair, the pair is suspended by failure to prevent the host I/O response delay. Mode 784 = OFF: The operation is processed in accordance with the TC, TCz, or GAD specification. Notes: This SOM is applied to the environment where OPEN host time-out time is set to 15 seconds or less. This SOM is applied to reduce RI/O MIH time to 5 seconds. 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. 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 by CCI is not "5 seconds" but is what was set at RI/O registration. If suspension by failure occurs while a TC, TCz, or GAD pair is being created or resynchronized when SOM 784 is set to ON, check the remote path status and the status of load on the device, take measures against the failure, and then resynchronize the pair. If a failure occurs on the switched path between storage systems, Mainframe host MIH or Open server time-out may occur. 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. 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. 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. Operation commands are not available for promptly switching to an alternate path. This SOM works for the pair for which initial pair creation or Resync operation is executed. Micro-program downgrade to an unsupported version cannot be executed unless all the TC, TCz, and GAD pairs are suspended or deleted. For operational specifications in each combination of MCU and RCU of TC or TCz, contact customer support (see SOM784 sheet). For GAD pairs, this SOM is effective if the microcode version supports GAD. 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 also not supported. (For TCz) If suspension by failure occurs while a TCz pair is being created or resynchronized when SOM 784 is set to ON, check the remote path status and the status of load on the device, take measures against the failure, and then resynchronize the pair. SOM 784 is supported only when the port type of all remote paths in one remote connection is Fibre. SOM 784 is not supported when the port type of all remote paths in one remote connection is iSCSI or iSCSI and Fibre.	Both
789	ShadowImage ShadowImage for Mainframe	Copy threshold option that operates during I/O from the host server to the primary volume. 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 in the CLPR containing the copy target S-VOL is suppressed to the minimum. Mode 789 = ON (default): If the cache write pending rate of the MP unit of the CLPR containing the copy target S-VOL 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 cache write pending rate of the MP unit of the CLPR containing the copy target S-VOL is in the following status, the copy processing caused by the I/O on the P-VOL is suppressed. Note that, if the cache write pending rate is high, the I/O performance on the volumes in the CLPR containing the copy target S-VOL might be degraded. When a V-VOL with capacity saving enabled is used as 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 a V-VOL with capacity saving enabled is used as 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 a V-VOL with capacity saving enabled is used as the P-VOL and S-VOL, copy processing is suppressed when the Write Pending rate is 90% or more.	-
790	ShadowImage ShadowImage for Mainframe	Copy threshold option that operates during I/O from the host server to the secondary volume. 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 in the CLPR containing the copy target S-VOL is suppressed to the minimum. Mode 790 = ON (default): When the cache write pending rate of the MP unit of the CLPR containing the copy target S-VOL is 60% or more, the copy processing caused by the I/O from the host server to the P-VOL is suppressed. Mode 790 = OFF:When the cache write pending rate of the MP unit of the CLPR containing the copy target S-VOL is in the following status, the copy processing caused by the I/O on the S-VOL is suppressed. Note that, if the cache write pending rate is high, the I/O performance on the volumes in the CLPR containing the copy target S-VOL might be degraded. 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.	-
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: 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. This SOM is available only when SOM 467 is set to ON. 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.	-
896	Dynamic Provisioning Dynamic Provisioning for Mainframe Thin Image Advanced	This SOM enables or disables the background format function performed on an unformatted area of a DP/TIA pool. For information regarding operating conditions, see the Provisioning Guide. Mode 896 = ON: The background format function is disabled. Mode 896 = OFF (default): The background format function is enabled. Notes: This SOM is applied when you need to disable the background format for a DP/TIA pool due to a concern of performance degradation of other functions in an environment where a DP-VOL is used by other functions. 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. 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. If the background format function is disabled by changing this SOM setting, the format progress is initialized and the entire area becomes unformatted.	-
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: 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. During I/O synchronous copy, host I/O performance degrades.	-
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: 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. During I/O synchronous copy, host I/O performance degrades.	-
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: 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 CLPR used only for UR/URz JNLG Since CM capacity allocated to MPBs with low load is small, the performance is affected by a sudden increase in load. 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. 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.	Both
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. Mode 972 = ON: The THP page size is 0x200 (256KB) regardless of the SOM 973 setting. Mode 972 = OFF (default): When SOM 972 is OFF and SOM 973 is ON, the THP page size is 0x10 (8KB). When SOM 972 and SOM 973 are both OFF, the THP page size is 0x15000 (42MB). Notes: This SOM is applied when a delay in host I/O response due to reclamation processing occurs in a customer environment. Reclamation processing is delayed. 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).	-
976	Universal Replicator for Mainframe	When this SOM is applied, differential copying by delta resync in tandem with IBM^® Hyperswap succeeds in the 3DC multi-target configuration using delta resync. However, when this SOM is set to ON, if the TCz S-VOL status becomes BCM SWAPPING, the restore operation for the URz pair is suppressed until delta resync is performed. Make sure that you perform delta resync after you set the TCz S-VOL in SWAPPING status. If you do not, delete the URz pair for delta resync and recreate it. The default is OFF.	Both
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: 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. 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.	-
1043	Universal Replicator Universal Replicator for Mainframe	This SOM disables journal copy. Mode 1043 = ON: When the following conditions are met at the UR/URz secondary site, the journal copy is disabled. The following conditions (1) and (2) or (1) and (3) are met: 4,096 or more journals are accumulated at the secondary site. The CLPR write pending rate for journal volumes of the MPB/MPU where journal ownership at RCU is defined is 25% or higher (including the write pending rate for other than journal volumes). 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: This SOM applies when one of the following conditions is met: Multiple journals are registered in a consistency group of CCI/BCM. Multiple journals are registered in an extended consistency group. Journals are accumulated at the secondary site, causing the system performance to decrease. 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. When the host write speed is faster than the JNL copy speed, the usage rate of the master journal increases. 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. 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.)	Both
1068	Common	This SOM 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: 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 SOM 144 sheet). Notes: Apply this SOM to detect a minor delay in drive response. When a delay is suspected, a processing to refer to the statistics data and determine the delay works. If SOM 157 is set to ON, the output prevention status of SSB=A4CE is not cleared in one-day cycle. 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.	-
1069	Common	By setting this SOM, the INQUIRY Page E3h field is changed (byte 3, bytes 8-11, bytes 50-53). The field varies depending on the combination of SOMs 972, 973, and 1069. Mode 1069 = ON: Byte 3, Additional Length, is 32h regardless of the SOM 972 and SOM 973 settings. Byte 8-11, Page Size (number of blocks), is 0x1500 (42MB) regardless of the SOM 972 and SOM 973 settings. Byte 50-53, Optional Write Same Granularity (number of blocks), is 0x200 (256KB) when SOM 972 is ON regardless of the SOM 973 setting. Byte 50-53 is 0x10 (8KB) when SOM 972 is OFF and SOM 973 is ON. Byte 50-53 is 0x1500 (42MB) when both SOM 972 and SOM 973 are OFF. Mode 1069 = OFF (default): Byte 3, Additional Length, is 2h regardless of the SOM 972 and SOM 973 settings. Byte 8-11, Page Size (number of blocks), is 0x200 (256KB) when SOM 972 is ON regardless of the SOM 973 setting. Byte 8-11 is 0x10 (8KB) when SOM 972 is OFF and SOM 973 is ON. Byte 8-11 is 0x1500 (42MB) when both SOM 972 and SOM 973 are OFF. Byte 50-53, Optional Write Same Granularity (number of blocks), is not applicable. Notes: 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. When this SOM is set to ON, reclamation processing is delayed. The priority of setting when SOMs are set at the same time is SOM 1069, 972, and then 973. The setting of higher priority SOM is enabled.	-
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 CTG is performed for 50 msec. Mode 1070 = OFF (default): The status change of all pairs in a CTG is performed for 1 msec. Notes: This SOM is applied when reducing the time to complete status change of all pairs in a CTG 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. The MP usage rate increases during status change of all pairs in a CTG. For details about approximate percentage increase in MP usage rate, contact customer support (see SOM1070 sheet).	Both
1080	Global-active device Universal Volume Manager	Use this SOM when 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 has degraded. For such a case, this SOM can eliminate the impact 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 impact 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 15 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: This SOM 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. When connection performance degradation occurs, the quorum disk blockage is more likely to occur.	Both
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: 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. When SOM 1083 is set to ON, the data of external volumes cannot be guaranteed. When DP-VOL deletion is performed without disconnecting an external volume, the data of the external volume cannot be guaranteed.	-
1086	Dynamic Provisioning Dynamic Provisioning for Mainframe Universal Volume Manager	This SOM enables or disables the performance improvement for DP-VOLs that are external volumes used as pool volumes. Mode 1086 = ON (default): The performance improvement is enabled. Mode 1086 = OFF: The performance improvement is disabled. Notes: 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. 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.)	-
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 SOM is used to disable this function. 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. 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: The SOM is applied when a significant delay, which is about 200 msec or longer, occurs in the line between MCU and RCU. When the 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. Even though the SOM is supposed to be applied to UR RCU, apply it to both MCU and RCU on the premise of DR operation. The SOM is effective for each CLPR, so that select the operation target LPRxx (xx=00 to 31), and then set the SOM to ON/OFF. For example, when only CLPR0 is defined (CLPR1 to 31 are not defined), select LPR00 and then set the SOM to ON/OFF. The SOM is not effective for any CLPRs if “System” is selected even when the SOM is set to ON.	Both
1097	Open	This SOM disables the warning LED to blink when specific SIMs are reported. Mode 1097 = ON (default): When SIM=452XXX, 462XXX, 3077XY, 4100XX, or 410100 is reported, the warning LED does not blink. Mode 1097 = OFF: 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.	-
1106	Dynamic Provisioning Dynamic Provisioning for Mainframe	This SOM is used (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, or (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: 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. 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. Examples: In a DP 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%. The difference in usage rate between each parity group and the average is 10% at the maximum. In a DP 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%. The difference in the usage rate between each parity group and the average is 30% at the maximum. 2: Condition for rebalance after 0 data page reclamation When the SOM is set to ON, rebalance works even when reclaimed page is 0 at 0 data page reclamation. Notes: The SOM is applied when balancing the usage rate is required at a customer site where the usage rate is not even. 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.	-
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. Note: While the capacity reduction processing is not working, the capacity saving rate might degrade. Mode 1113 = OFF (default): The capacity saving function fully works. Notes: This SOM 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. When this SOM is set to ON, the capacity reduction processing does not work and the capacity saving rate degrades. SOM 1113 is related to SOM 1112. When both SOMs are set to ON, the setting of SOM 1112 is prioritized over that of SOM 1113. Behavior when SOM 1112 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.	-
1169	Dedupe and Compression	This SOM 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: Deduplication processing is not performed during resync processing.* Mode 1169 = OFF (default): 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.	-
1182	Universal Replicator	Enable this SOM when you replace the primary site journal volume for the UR delta resync pair shared with GAD with a reserve journal volume. Mode 1182 = ON: In a configuration where GAD and UR are linked, if the reserve journal is added as the primary site journal for the delta resync pair, the status of the journal group changes to HLDE. In a configuration where GAD and UR are linked, you can delete the primary site journal for the delta resync pair if the status of the journal is HLDE. Mode 1182 = OFF (default): In a configuration where GAD and UR are linked, this setting prevents journal volumes from being deleted when the status of the primary site journal for the delta resync pair is HOLD , HOLDING, or HLDE. If a reserve journal volume is already added, delete the reserve journal volume from the journal, set SOM 1182 to ON, and then add a reserve journal volume again. When the journal volume is successfully replaced, restore the status of the delta resync pair.	MCU
1198	TrueCopy	This SOM enables users to switch the difference management method by setting the SOM to ON from CCI. At TC pair creation or resync operation, the difference management method is switched from SM difference management to hierarchy difference management. * The behavior when the SOM is ON or OFF differs from that when advanced system setting No. 5 or No. 6 is set to ON or OFF. Mode 1198 = ON: The behavior varies depending on the setting combination of SOM 1198 and SOM 1199. For details, contact customer support (see SOM1198_1199 sheet). Mode 1198 = OFF (default): The behavior varies depending on the setting combination of SOM1198 and SOM1199. For details, contact customer support (see SOM1198_1199 sheet). Notes: This SOM is applied to enable users to use CCI in TC operations to perform capacity expansion for volumes with 4TB or less used in TC pairs. Setting the SOMs affects the I/O response performance depending on the I/O pattern. Setting the SOMs affects the initial copy time depending on the conditions.	Both
1199	Global-active device	This SOM enables 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. At TC pair creation or resync operation, the difference management method is switched from hierarchy difference management to SM difference management. * The behavior when the SOM is ON or OFF differs from that when advanced system setting No. 5 or No. 6 is set to ON or OFF. Mode 1199 = ON: The behavior varies depending on the setting combination of SOM 1198 and SOM 1199. For details, contact customer support (see SOM1198_1199 sheet). Mode 1199 = OFF (default): The behavior varies depending on the setting combination of SOM 1198 and SOM 1199. For details, contact customer support (see SOM1198_1199 sheet). Notes: This SOM is applied to enable users to use CCI in TC operations to switch difference management method from hierarchy difference management to SM difference management for volumes of 4TB or less used in TC pairs. Setting the SOMs affects the I/O response performance depending on the I/O pattern. Setting the SOMs affects 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. 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 the 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 SOM is set to OFF. Even when the SOM is set to ON, the I/O mode of a volume of the other storage system does not always change to Local. (The SOM is effective in the case that the I/O mode of the P-VOL is Local while the SOM is set to OFF.) Note: The SOM is applied if 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
1204	Dynamic Provisioning Dynamic Provisioning for Mainframe Thin Image Advanced	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 sheet SOM 1204). Notes: This SOM is applied 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. 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. When SOM 904 is set to ON, the SOM 904 setting is prioritized. 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.	-
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: 4096 or more journal data sets are accumulated on RCU. The write pending rate of a journal volume in an MPB that has the ownership of the journal on RCU exceeds the threshold, 25% (SOM OFF) or 50% (SOM ON). (Including the write pending rate of those other than the journal volume) 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: Apply this SOM when any of the following conditions is met: Disabling journal data copy is enabled by meeting one of the following conditions: SOM 1043 is set to ON for each CLPR on the secondary site. A configuration where multiple journals are added to a CCI/BCM consistency group. If the host write I/O speed is faster than the journal data copy speed, the usage of the master journal increases. Though this SOM can work on UR/URz RCU, apply it to both MCU and RCU assuming a Disaster Recovery operation. This SOM is related to SOM 1043. 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 SOM. This SOM is effective per CLPR. Therefore, select a target LPR xx (xx= 00 to 31), and then set the SOM to ON or OFF. For example, when setting the SOM to CLPR0 (even though CLPR 1 to 31 are not defined), select LPR00, and then set the SOM to ON or OFF. If you just select System and then set the SOM, the SOM cannot be enabled for any CLPRs.	Both
1224	ShadowImage ShadowImage for Mainframe Thin Image Volume Migration Universal Replicator Universal Replicator for Mainframe	The SOM 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 1225 = 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 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: Apply the SOM when preventing the MP usage rate increase is required. Ownerships are in a specific MPU so that I/Os may be concentrated on the MPU. 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	Dedupe and Compression FlashCopy^® Global-active device ShadowImage ShadowImage for Mainframe Volume Migration Thin Image Advanced TrueCopy TrueCopy for Mainframe Universal Replicator Universal Replicator for Mainframe	This SOM 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 replication products* that run in the background. * Replication products: FlashCopy^®, GAD, SI, SIz, TC, TCz, TIA, UR, URz, VM. Mode 1254 = ON: GAD, SI, SIz, TIA, TC, TCz, UR, URz, VM: 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: FC: Background copy, update copy (Restore), update copy (Reverse Restore), update copy (Fast Reverse Restore) 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. TIA: Copy processing by restore, copy processing by clone VM: Pair initial copy Mode 1254 = OFF (default): SI/SIz, TIA, VM: As per the SOM 467 setting. GAD, TC/TC: As per the SOM 689 setting. UR/URz: As per the SOM 690 setting.	Both
1260	Dedupe and Compression Global-active device ShadowImage TrueCopy Universal Replicator Volume Migration	This SOM 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. (): SI, VM, Thin Image, TC, GAD, UR. Mode 1260 = ON: SI, VM, TI, TC, GAD, UR: The copy processing running in the background* stops when the WP rate of the copy target volume is 35% or higher. Mode 1260 = OFF (default): SI, VM, TI: As per the SOM 467 setting. TC, GAD: As per the SOM 689 setting. UR: As per the SOM 690 setting. * The copy processing running in the background refers to the following processing: SI: 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. TI: Copy processing by restore, copy processing by clone. TC: 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: Apply the SOM 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 volume is 35% or higher. Setting the SOM per CLPR is required. (Setting for all CLPRs, use SOM 1254.) The SOM setting for a CLPR of UR S/VOL, and that for a CLPR of a journal volume are the same. (The SOM is set to ON or OFF for both CLPRs.) 1: Note that in CLPRs with the SOM 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. By setting the SOM 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. 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 volume is 35%. SOM 1260 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. Recovering a pair that is suspended due to failure takes longer time too. 2: Note that in CLPRs with the SOM 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. When UR 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, use different CLPRs for the UR S-VOL and the journal volume, and for the DRD-VOL for which preventing performance degradation is required on RCU, and set the SOM to ON for the CLPR of the DRD-VOL only. 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. 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 1260 disabled. When UR 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 the UR 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 S-VOL and the journal volume, and for a DRD-VOL for which preventing performance degradation is required on MCU too. 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.	Both
1260	Dedupe and Compression Global-active device ShadowImage ShadowImage for Mainframe TrueCopy TrueCopy for Mainframe Universal Replicator Universal Replicator for Mainframe Volume Migration	This SOM is used to prevent the performance of a host I/O to a DRS-VOL in the specified CLPR from being degraded due to the copy processing of a replication program product () that runs on the background. (): SI, VM, Thin Image, TC, GAD, UR. Mode 1260 = ON: SI, VM, TI, TC, GAD, UR: The copy processing running in the background* stops when the WP rate of the copy target volume is 35% or higher. Mode 1260 = OFF (default): SI, VM, TI: As per the SOM 467 setting. TC, GAD: As per the SOM 689 setting. UR: As per the SOM 690 setting. * The copy processing running in the background refers to the following processing: SI: 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. TI: Copy processing by restore, copy processing by clone. TC: 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: Apply the SOM 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 volume is 35% or higher. Setting the SOM per CLPR is required. (Setting for all CLPRs, use SOM 1254.) The SOM setting for a CLPR of UR S/VOL, and that for a CLPR of a journal volume are the same. (The SOM is set to ON or OFF for both CLPRs.) 1: Note that in CLPRs with the SOM 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. By setting the SOM 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. 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 volume is 35%. SOM 1260 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. Recovering a pair that is suspended due to failure takes longer time too. 2: Note that in CLPRs with the SOM 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. When UR 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, use different CLPRs for the UR S-VOL and the journal volume, and for the DRD-VOL for which preventing performance degradation is required on RCU, and set the SOM to ON for the CLPR of the DRD-VOL only. 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. 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 1260 disabled. When UR 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 the UR 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 S-VOL and the journal volume, and for a DRD-VOL for which preventing performance degradation is required on MCU too. 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.	Both
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 SOM 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 SOM 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 metadata 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: Apply this SOM 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. By setting the SOM to ON, the capacity saving ratio may decrease. When an adaptive data reduction setting change is complete after setting the SOM to ON, set the SOM to OFF.	-
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: Apply the SOM 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). 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
1282	Universal Volume Manager	SOM 1282 determines whether to report SIM=21D2XX when all the following conditions are met. The timeout value for an I/O issued to an external volume is set to 16 seconds or longer. After a command is run for an external storage system, the number of times a normal response to an issued I/O takes 15 seconds or longer reaches 50 or more within one hour. Mode 1282 = ON: SIM=21D2XX is reported if the number of times a normal response to an issued I/O takes 15 seconds or longer reaches 50 or more within one hour per external volume/path after a command is run for an external storage system. Mode 1282 = OFF (default): SIM=21D2XX is not reported if the number of times a normal response to an issued I/O takes 15 seconds or longer reaches 50 or more within one hour per external volume/path after a command is run for an external storage system. Supplemental information: As per the existing specifications, regardless of the SOM 1282 settings, SIM=21D2XX is reported if the number of times that the timeout of I/Os issued to an external storage system occurs per external volume/path within one hour reaches 10 or more. Notes: Apply the SOM when: The timeout value for an I/O issued to an external volume is set to 16 seconds or longer. A SIM report for a delay in response from an external storage system is required. Regardless of the SOM 1282 settings, SIM=21D2XX is reported if the number of times that the timeout of I/Os issued to an external storage system occurs per external volume/path within one hour reaches 10 or more. When SIM=21D2XX is reported by the function of SOM 1282, 0F is set in the 103(67h) byte of the related SSB=AD60. If SIM=21D2XX is reported due to I/O timeout, 0C is set in the 103(67h) byte of the related SSB=AD60.	-
1293	Global-active device	This SOM is used to enable or disable GAD pair initial copy when one side of cache PCBs is blocked. Mode 1293 = ON: When one side of cache is blocked, GAD pair creation, resync, and swap resync are available. Mode 1293 = OFF (default): When one side of cache is blocked, GAD pair creation and resync are not available. Notes: Host performance will be degraded due to increase in drive load, and initial copy performance will tend to be degraded compared to normal status of the cache if initial copy is performed when one side of cache is blocked. If unacceptable host performance degradation occurs, stop the initial copy. If initial copy works while one side of cache is blocked, the host performance is degraded due to increase in drive load and the initial copy performance tends to be degraded compared to when the cache is in normal status. If unacceptable host performance degradation occurs, stop the initial copy. If the host performance or the initial copy performance at blockage of one side of cache is prioritized, consider setting SOM 164 too, which can disable write through. Cache maintenance operations cannot be performed while initial copy is running. To perform a cache maintenance operation, stop the initial copy. Set this SOM to ON for both MCU and RCU storage systems. For example, if this SOM is set to ON for MCU only, and one side of cache is blocked on the RCU, the SOM function does not take effect.	Both
1299	Dedupe and Compression	When the de-staging performance is not enough for a reason such as high PG usage rate, the asynchronous processing of capacity saving may cause the cache write pending rate to increase, so that the write response performance may be degraded. For the issue, this SOM is available to disable the asynchronous processing of capacity saving if the cache write pending rate is 30% or higher. Mode 1299 = ON: When the write pending rate of a CLPR containing a virtual volume on which the following asynchronous processing runs is 30% or higher, the asynchronous processing is disabled. (The processing of capacity saving other than those listed is not disabled.) Disabling capacity saving Deleting an LDEV with capacity saving enabled Garbage collection Asynchronous data reduction Compression conversion of compression accelerator Garbage collection to collect unnecessary metadata and user data of a deduplication system data volume (data store) Deleting unnecessary hash data for capacity saving Expanding metadata area of capacity saving Control information correction when SOM 1208 is set to ON Health check when SOM 1237 is set to ON Mode 1299 = OFF: The above asynchronous processing runs as usual. Notes: Apply the SOM when it is acceptable that the pool usage rate increases up to the warning threshold when the cache write pending rate is continuously at 30% or higher, and preventing the asynchronous processing of capacity saving from affecting the write response performance is required. If the cache write pending rate is continuously at 30% or higher, the capacity saving ratio might deteriorate.	-
1329	Universal Replicator	When one side of cache is blocked on MCU, this SOM enables UR pair creation, resync, and swap resync. When one side of cache is blocked on RCU, UR pair creation, resync and swap resync are available regardless of the setting of this SOM. However, when you set this SOM to ON on MCU, we recommend that you also set this SOM to ON on RCU, considering the case in which the P-VOL and S-VOL are replaced due to disaster recovery or some other reason. Mode 1329 = ON: UR pair creation, resync, and swap resync are available. Mode 1329 = OFF (default): UR pair creation, resync, and swap resync are not available. Notes: When this SOM is set to ON, if initial copy of the UR pair is performed when one side of cache is blocked, the following adverse effects might occur: The load on the drive increases, which affects host performance. Performance of initial copy is degraded compared to when the cache is in the normal state. The blocked cache cannot be maintained during initial copy. If unacceptable host performance degradation occurs or maintenance of the blocked cache is performed, stop the initial copy. (VSP One B20 series) This SOM can be used for the following DKCMAIN microcode versions: A3-04-21-x0/00 or later (Universal Replicator).	Both
1330	TrueCopy	This SOM enables TC pair creation, resync, and swap resync when one side of cache is blocked. Mode 1330 = ON: TC pair creation, resync, and swap resync are available. Mode 1330 = OFF (default): TC pair creation, resync, and swap resync are not available. Notes: When this SOM is set to ON, if initial copy of the TC pair is performed when one side of cache is blocked, the following adverse effects might occur: The load on the drive increases, which affects host performance. Performance of initial copy is degraded compared to when the cache is in normal state. The blocked cache cannot be maintained during initial copy. If unacceptable host performance degradation occurs or maintenance of the blocked cache is performed, stop the initial copy. (VSP One B20 series) This SOM can be used for the following DKCMAIN microcode versions: A3-04-21-x0/00 or later.	Both