HP XP P9500 Storage - Manual (Page 100)

Prerequisite information
•
For information and illustrations on the configuration covered in this procedure, see “Delta
resync configuration ” (page 144) .
•
You can specify options for recovery in the event that the delta resync operation fails. See the
Delta resync Failure step in
“Changing options used by mirrors ” (page 82) . This also provides
important information if you share the delta resync S-VOL with Business Copy, Fast Snap, or
Snapshot and a THP V-VOL.
Procedure 37 To recover a delta resync configuration failure
1. Run the horctakeover command on the Cnt Ac-S pair.
2. Start host operations to the Cnt Ac-S S-VOL.
3. Perform the delta resync operation on the volume in the Cnt Ac-S intermediate site.
See “Prerequisite information for delta resync operation ” (page 147) .
Note that pair status must be HOLD before the operation. When the operation completes,
pair status is PAIR or COPY.
NOTE: Pair status also changes for the original Cnt Ac-J pair in the primary and Cnt Ac-J
remote sites, from PAIR or COPY to HOLD.
However, the status of the original pair may not change to the required state after the delta
resync operation. If this occurs, host operations cannot be resumed in the primary site. See
“Problems with pair status during delta resync recovery” (page 100) and make the necessary
corrections.
4. Restore the problem at the primary site. This must be done before proceeding.
5. If the Cnt Ac-S pair is suspended, resynchronize the pair and reverse the copy flow.
6. Stop host operations to the Cnt Ac-S intermediate site.
7. Run the horctakeover command on the Cnt Ac-S pair.
8. Resume host operations to the Cnt Ac-S P-VOL in the primary site.
9. Perform the delta resync operation on the volume in the Cnt Ac-S primary site. Pair status must
be HOLD. When the operation completes, pair status is PAIR or COPY.
Also, pair status changes for the delta resync Cnt Ac-J pair from the Cnt Ac-S intermediate to
the Cnt Ac-J remote site, from PAIR, PSUS, or PSUE to HOLD.
The system becomes a delta resync configuration again.
Problems with pair status during delta resync recovery
After performing the delta resync, it is necessary for the original Cnt Ac-J pair from the primary to
Cnt Ac-J remote sites to be in HOLD status, in order to resume operations at the primary site.
However, the pair may not be in this status.
If pair status is not HOLD, match the pair’s actual statuses in the following table and then perform
the corrective action.
Corrective action Current status
Primary site: PAIR or COPY 1. Make sure that the status of the pair in the primary site is PSUE or PSUS.
Cnt Ac-J secondary site: HOLD 2. Release the Cnt Ac-J pair from the primary site.
100 Disaster recovery operations