IBM DS8900F, Introduction And Planning Manual

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Change recording
Activates the change recording function on the volume pair that is participating in a FlashCopy
relationship. This function enables a subsequent refresh to the target volume.
Establish FlashCopy on existing Metro Mirror source
Establish a FlashCopy relationship, where the target volume is also the source of an existing remote
mirror and copy source volume. This allows you to create full or incremental point-in-time copies at a
local site and then use remote mirroring commands to copy the data to the remote site.
Fast reverse
Reverses the FlashCopy relationship without waiting for the finish of the background copy of the
previous FlashCopy. This option applies to the Global Mirror mode.
Inhibit writes to target
Ensures that write operations are inhibited on the target volume until a refresh FlashCopy operation is
complete.
Multiple Incremental FlashCopy
Allows a source volume to establish incremental flash copies to a maximum of 12 targets.
Multiple Relationship FlashCopy
Allows a source volume to have multiple (up to 12) target volumes at the same time.
Persistent FlashCopy
Allows the FlashCopy relationship to remain even after the FlashCopy operation completes. You must
explicitly delete the relationship.
Refresh target volume
Refresh a FlashCopy relationship, without recopying all tracks from the source volume to the target
volume.
Resynchronizing FlashCopy volume pairs
Update an initial point-in-time copy of a source volume without having to recopy your entire volume.
Reverse restore
Reverses the FlashCopy relationship and copies data from the target volume to the source volume.
Reset SCSI reservation on target volume
If there is a SCSI reservation on the target volume, the reservation is released when the FlashCopy
relationship is established. If this option is not specified and a SCSI reservation exists on the target
volume, the FlashCopy operation fails.
Remote Pair FlashCopy
Figure 4 on page 46 illustrates how Remote Pair FlashCopy works. If Remote Pair FlashCopy is used
to copy data from Local A to Local B, an equivalent operation is also performed from Remote A to
Remote B. FlashCopy can be performed as described for a Full Volume FlashCopy, Incremental
FlashCopy, and Dataset Level FlashCopy.
The Remote Pair FlashCopy function prevents the Metro Mirror relationship from changing states and
the resulting momentary period where Remote A is out of synchronization with Remote B. This feature
provides a solution for data replication, data migration, remote copy, and disaster recovery tasks.
Without Remote Pair FlashCopy, when you established a FlashCopy relationship from Local A to Local
B, by using a Metro Mirror primary volume as the target of that FlashCopy relationship, the
corresponding Metro Mirror volume pair went from "full duplex" state to "duplex pending" state if the
FlashCopy data was being transferred to the Local B. The time that it took to complete the copy of the
FlashCopy data until all Metro Mirror volumes were synchronous again, depended on the amount of
data transferred. During this time, the Local B would be inconsistent if a disaster were to have
occurred.
Note: Previously, if you created a FlashCopy relationship with the Preserve Mirror, Required option,
by using a Metro Mirror primary volume as the target of that FlashCopy relationship, and if the status
of the Metro Mirror volume pair was not in a "full duplex" state, the FlashCopy relationship failed. That
restriction is now removed. The Remote Pair FlashCopy relationship completes successfully with the
"Preserve Mirror, Required" option, even if the status of the Metro Mirror volume pair is either in a
suspended or duplex pending state.
Chapter 3. Data management features 45