Sharing a Compatible FlashCopy S-VOL and a TCz volume

Compatible FlashCopy User Guide for VSP One Block 85

Version

10.5.x

Audience

anonymous

Part Number

MK-26VSP1B031-02

ft:lastEdition

2026-05-04

When sharing a Compatible FlashCopy^® S-VOL and a TrueCopy for Mainframe (TCz) volume, or when using the Remote FlashCopy^® function, you must do the following:

If the Compatible FlashCopy^® S-VOL is shared with the TCz S-VOL, specify only one Compatible FlashCopy^® T-VOL.
If the Compatible FlashCopy^® S-VOL is shared with the TCz S-VOL, specify a volume of the same emulation type and capacity as the Compatible FlashCopy^® S-VOL.
Set system option modes (SOMs) 20 and 190 to ON in the RCU.
Use a volume with an emulation type listed in Supported emulation type combinations.

When you share a Compatible FlashCopy^® S-VOL and a volume of a TCz pair, the status of the TCz pair must be either Duplex, Pending, or Suspend. If the shared TCz volume is an S-VOL, there may be cases when you might not be able to create the Compatible FlashCopy^® relationship, as described in the following table.

Table. Shared volume: Compatible FlashCopy^® S-VOL and TCz
Shared TCz volume		Status of TCz pair
Shared TCz volume		Duplex	Pending	Suspend
TCz	P-VOL	OK	OK¹	OK
TCz	S-VOL^{3, 4, 5, 6, 7}	OK	No²	OK
Notes: If a TCz P-VOL is in Pending status and you execute an ICKDSF command for Compatible FlashCopy^®, the ICKDSF job will end abnormally with CC=12 error. For information about how to avoid that abnormal ending, see ICKDSF command terminates abnormally. You cannot establish the Compatible FlashCopy^® relationship, because the data consistency of the Compatible FlashCopy^® T-VOL will not be ensured. If you establish a Compatible FlashCopy^® relationship with the FREEZE option when the TCz S-VOL is shared with the Compatible FlashCopy^® source volume, the results of operations differ depending on the type of storage systems at the TCz primary and secondary sites. For details, see Volumes that can be shared. Regardless of the type of storage systems at the TCz primary and secondary sites, if a TCz pair is registered in a consistency group, commands are rejected and the Compatible FlashCopy^® relationship cannot be established. If a Compatible FlashCopy^® relationship is established with the FREEZE option, when the TCz S-VOL is shared with the Compatible FlashCopy^® source volume, and when the TCz S-VOL is in the extended long busy (ELB) state, the command to create or resume a pair will be rejected. However, the command to split or delete a pair will be executed normally. When the TCz S-VOL is shared with the Compatible FlashCopy^® source volume, a Compatible FlashCopy^® relationship might not be established due to a timeout error. The timeout error occurs if you restart the primary or secondary site after creating a TCz pair, and then establish a Compatible FlashCopy^® relationship with the FREEZE option. Restarting the primary or secondary site includes the following operations: Turning off the power, and then turning it on again (restarting after a planned shutdown). Forcibly turning off the power of the DKC or DKU, and then turning it on again. Replacing the microcodes offline. To avoid this problem, suspend the TCz pair after restarting the primary or secondary site, and then resynchronize the TCz pair. After that, establish a Compatible FlashCopy^® relationship. If you establish a Compatible FlashCopy^® relationship with the FREEZE option when the TCz S-VOL is shared with the Compatible FlashCopy^® source volume, communications can be performed between the TCz primary and secondary site. If you remove a remote path for some remote copy connections at this time, there are no valid remote paths that can be communicated, and therefore, the Compatible FlashCopy^® relationship operations might not be performed. In this case, a valid communication path can be re-established by performing either of the following operations: Issue update I/O to the TCz pair. Suspend the TCz pair, and then resynchronize them. TrueCopy for Mainframe allows remote data transfer to happen in parallel to provide excellent remote copy performance. Under certain circumstances, establishing a FlashCopy^® relationship with the FREEZE option from, for example, a TCz secondary volume, can impact operating times due to the extra communication between the TCz primary and secondary volumes to guarantee data consistency.

Table. **Operation results when the TCz S-VOL is shared with a Compatible FlashCopy^® source volume, and a Compatible FlashCopy^® relationship is established with the FREEZE option**
Storage systems at TCz primary and secondary sites		Operation results
VSP One Block 85 at both the primary and secondary sites		A Compatible FlashCopy^® relationship can be established. As with the case of when volumes are not shared with TCz, writing to the P-VOL of a TCz pair will be suspended until the FREEZE state (a state in which writing to the source volume is suspended) is released after a Compatible FlashCopy^® relationship has been established. To perform this operation, set the SCP time for theTCz S-VOL to something other than the default of 2 minutes. For SCP time settings, see Suspending write operations to S-VOLs when establishing Compatible FlashCopy^® V2 relationships. To release the FREEZE state, execute the FCWITHDR command with the ACTION parameter for the source volume of the Compatible FlashCopy^® relationship. For details, see Releasing Compatible FlashCopy^® V2 relationships. In the following cases, the FREEZE state is automatically released on the primary site state, the secondary site state remains until the SCP set time: When you set the SCP time longer than 2 minutes and 2 minutes and 10 seconds have passed. When TCz pair is suspended.

When using with TCz older models, see the corresponding User Guide.

When you use a Compatible FlashCopy^® source volume as a TCz S-VOL, configure the system as follows:

Connect the different hosts to the local storage system and remote storage system, or connect the host of the local storage system to both the local and remote storage systems.
Use an iSCSI or Fibre Channel interface to connect the local storage system with the remote storage system.

The above combinations are different from when IBM^® FlashCopy^® and PPRC are used in conjunction.

The following table describes whether Reverse Restore can be performed when you share a Compatible FlashCopy^® S-VOL and a volume of a TCz pair.

Table. Reverse Restore when a Compatible FlashCopy^® S-VOL is used as a TCz volume
Shared TCz pair volume		Status of TCz pair
Shared TCz pair volume		Duplex	Pending	Suspend
TCz	P-VOL	OK*	OK*	OK*
TCz	S-VOL	No	No	No
* You can perform Reverse Restore by specifying the following options listed for each host interface: DFSMSdss: `FCTOPPRCPRIMARY` (You cannot perform Fast Reverse Restore when using DFSMSdss.) TSO: `TGTPPRIM`(`YES`) ICKDSF: `TGTOKASPPRCPRIM`(`YES`) ANTRQST macro: `TGTPPRIM`(`YES`)

The following table shows whether Fast Reverse Restore can be performed when you share a Compatible FlashCopy^® S-VOL and a volume of a TCz pair.

Table. Fast Reverse Restore when a Compatible FlashCopy^® S-VOL is used as a TCz volume
Shared TCz pair volume		Status of TCz pair
Shared TCz pair volume		Duplex	Pending	Suspend
TCz	P-VOL	OK*	OK*	OK*
TCz	S-VOL	No	No	No
* You can perform Fast Reverse Restore by specifying the following options listed for each host interface: TSO: `TGTPPRIM`(`YES`) ICKDSF: `TGTOKASPPRCPRIM`(`YES`) ANTRQST macro: `TGTPPRIM`(`YES`)