Prerequisite – HP XP P9500 Storage User Manual
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Prerequisite information for delta resync operation
You perform the delta resync operation using the Resume Pair operation. After reviewing these
prerequisites, see
•
The delta resync P-VOL must be updated for longer than 5 minutes after the operation is
completed and pair status has changed to PAIR. However, a workaround is available that
allows you to avoid the 5-minute update requirement. See
“Assigning remote command devices
for details.
•
Required pair and volume statuses:
The Cnt Ac-S Z volume used as the 3DC multi-target S-VOL: Duplex or Swapping
◦
◦
The Cnt Ac-S Z S-VOL used as the delta resync P-VOL: Suspend.
Check this status after executing the BCM YKSUSPND REVERSE command and YKRESYNC
REVERSE command.
◦
The Cnt Ac-J Z delta resync pair: Hold or Holding. If the pair status is Hlde, change to
Hold by performing the pairresync operation.
This applies to all pairs in the journal in which the Cnt Ac-J Z pair for delta resync resides.
◦
The Cnt Ac-J Z volume used as the 3DC multi-target and the delta resync pair S-VOL and
uses two mirror IDs — one for the 3DC multi-target pair and one for the delta resync pair:
- 3DC multi-target S-VOL: Duplex or Suspended
- Delta resync S-VOL: Hold.
NOTE:
The Cnt Ac-J Z S-VOL uses two mirror IDs because of its dual use in the 3DC
multi-target and delta resync configurations. The statuses shown above are required for
the two mirrors as well as for the journal in which the Cnt Ac-J Z pair for delta resync
resides.
◦
If the delta resync S-VOL has been backed up on the remote site using BCZ or FS, make
sure to review the information for the Delta resync Failure step on the Change Mirror
Option window (
).
•
Differential data is stored in the master journal but may not be completely present after a
failure at the primary site when the pair was being recovered (or after creating the delta resync
pair configuration).
•
If data in the restore journal exceeds 80% of capacity, old journal data is automatically
deleted. This can occur when the suspended pair has not been re-synchronized for a long
time.
In this case, based on journal option settings, the entire P-VOL is copied to the S-VOL. In a
delta resync operation, processing is not performed.
•
Journal data may also be destroyed in the following cases:
When you restore the Cnt Ac-S Z or Cnt Ac-J Z pair in the multi-target configuration, then
also update the delta resync pair.
◦
◦
When retry-processing occurs because of a delay of the P-VOL update.
◦
When the update of a Cnt Ac-S Z S-VOL is delayed.
•
The Cnt Ac-J Z pair status in a delta resync configuration could become Suspend if you split
the pair, or if there is a failure when copying all data from the P-VOL to the S-VOL. If you then
run the delta resync operation, all data might be copied from P-VOL to S-VOL regardless of
journal option settings.
•
If the pair’s mirror is in Halting or Stopping status, the resume command is rejected.
Delta resync configuration
151