Preserve Mirror FlashCopy

You can choose to allow the target volume of a FlashCopy® operation to be a Peer-to-Peer Remote Copy (PPRC) primary device. When the tracks associated with the FlashCopy relationship are copied to the PPRC secondary device, the PPRC (Metro Mirror) pair goes into a duplex pending state, to ensure the integrity of the mirror between the local site and the remote site. When the FlashCopy operation completes, the PPRC_SYNC volume pair returns to full duplex state.

IBM® Remote Pair FlashCopy (also known as Preserve Mirror) mirrors the FlashCopy command that is issued at the local site, to the remote site. This allows FlashCopy operations to occur to PPRC primary volumes without affecting the PPRC duplex state.

When you specify the FCTOPPRCPrimary keyword on the COPY command, you are requesting that DFSMSdss allows a PPPRC primary volume to become the target volume of the FlashCopy operation. You can specify the following sub-keywords to indicate whether the PPRCP mirror is allowed to go to duplex pending state if the target volume of the FlashCopy operation is a metro mirror primary device:

PRESMIRREQ: specifies that if the target volume is a Metro Mirror Primary device, the pair must not go into a duplex pending state as the result of a FlashCopy operations.
PRESMIRPREF: specifies that if the target volume is a Metro Mirror primary device, it would be preferable that the pair does not go into a duplex pending state as the result of a FlashCopy operation. However, if a Preserve Mirror operation cannot be accomplished, the FlashCopy operation is still to be performed.
The PRESMIRPREF option is not valid for DS888x and newer, and compatible, storage subsystems. If the PRESMIRPREF option is specified and the volumes involved in the operation reside on DS888x or newer storage subsystems, the command results in a warning or error message. This is also true of the corresponding option provided in byte 33 (X'21') in the ADRUFO data area.
PRESMIRNONE: specifies that Preserve Mirror operation is not to be done, even if all of the configuration requirements for a Preserve Mirror operation are met. If the target specified is a Metro Mirror primary device, the pair is to go into a duplex pending state while the secondary device is updated with the tracks to be copied. PRESMIRONONE is the default if you specify FCTTOPPRCPrimary without a subkeyword.

Note: If the target volume of FlashCopy operation is not a metro mirror primary volume, then the FCTOPPRCPrimary keyword has no effect on the FlashCopy operation.

For more information about Peer-to-Peer Remote Copy (PPRC) and metro mirror operation, refer to z/OS DFSMS Advanced Copy Services.

For more information about the FCTOPPRCPrimary keyword on the COPY command, refer to COPY Command for DFSMSdss.