HP XP Business Copy Software - Manual (Page 108)

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the relationship of FlashCopy Mirror Version 2 to the executing of the update copy operation by the
Incremental FlashCopy function.
Figure 53 Incremental FlashCopy
When you issue a command to establish relationship, all the data of the S VOL will be copied to the T
VOL. If you specify a parameter for Incremental FlashCopy, the relationship will not be deleted even if the
copy operation from the S VOL to the T VOL is completed. When the S VOL is updated, the updated data
will be managed as differential data while the copy operation is in progress and while the relationship is
maintained. For example, in Figure 53 on page 108, "Data 2A" is managed as a differential data. If you
re-execute the command to establish the relationship, only the differential data of "Data 2A" will be copied
to the T VOL, and the data of the T VOL will be identical to the data of the S VOL.
CAUTION: If you want to use the Incremental FlashCopy function, replace the microprogram with the
microprogram which supports the function, and then re-execute the devserv command with the VALIDATE
option of QDASD to the devices in the subsystem. For information about the examples of executing the
devserv command see ” Installing Compatible Mirroring for IBM FlashCopy Version2 ” on page 115.
Reverse Restore Function
The Reverse Restore function allows you to simplify the procedure of data recovery in a time of disaster.
The Reverse Restore function is a recovery function that reverses the S-VOL and the T-VOL of a relationship
established by the Incremental FlashCopy function and then re-establishes the relationship.
However, you cannot perform the Reverse Restore in the following cases.
• Performing the Reverse Restore against the relationship established without using the Incremental
FlashCopy function.
• When the copy of the relationship has not be completed established in COPY mode.
• Performing the Reverse Restore against the relationship established in NOCOPY mode.
• Performing the Reverse Restore against the relationship which includes a volume established
relationship with mutiple volumes.
• Performing the Reverse Restore against the relationship which the S-VOL capacity exceeds the T-VOL
capacity.
You can judge whether the Reverse Restore function can be executed from the execution result of the
FLASHCOPY QUERY RELATIONS command of ICKDSF.