HP XP7 Storage - Manual (Page 89)

Resuming host operations at the local site
When Cnt Ac-J pairs are established in the reverse direction between the remote and local sites,
you can return host operations to the original configuration. This means resuming host operations
at the local site and reestablishing the original flow of data from primary to secondary systems.
The following procedure explains how to resume normal operations at the local site.
1.
At both sites, make sure that Cnt Ac-J components are operational.
2. Make sure that pair status of P-VOLs and S-VOLs in all Cnt Ac-J pairs is PAIR.
3. Stop host applications at the remote site.
4. Issue a request for splitting pairs to master journals (these were originally the restore journals
on the remote site); use the Flush option when splitting pairs. If an error occurs when splitting
pairs, fix the error, resume host operations at the remote site, and then go back to step 1.
5. If no errors occur, wait until suspension finishes. After suspension finishes, check for an S-VOL
on the local site whose status is not PSUS. If such a pair exists, fix the error and go back to
step 1 after resuming your business task at the remote site.
6. When all S-VOLs at the local site are in PSUS status, data in P-VOLs and S-VOLs are the same.
S-VOLs at the local site are ready for host read/write activity. Resume applications at the local
site.
7. Run the pairresync -swaps command, which reverses P-VOLs and S-VOLs and resynchronizes
the pairs. The replication is from the local site to the remote site (disaster recovery site).
NOTE: When you run the pairresync -swaps command, you can use the -d option to specify
a data volume. However, the command is rejected if the restore journal where the data volume
belongs is in Active, Halting or Stopping status.
Recovery for 3 Cnt Ac-J/Cnt Ac-S data centers
Recovery procedures when Cnt Ac-J P-VOLs and S-VOLs are shared with Continuous Access
Synchronous can be more complex than general procedures. The following topics provide recovery
procedures for resuming host operations at a backup site and then restoring the original system
and configurations.
•
“Recovery for 3 Cnt Ac-J/Cnt Ac-S DC cascade configuration ” (page 89)
•
“Recovery for 3 Cnt Ac-J/Cnt Ac-S DC multi-target configuration ” (page 90)
•
“Recovery in a delta resync configuration” (page 91)
•
“Recovery in a 2DC configuration ” (page 93)
Use RAID Manager to perform all procedures.
Recovery for 3 Cnt Ac-J/Cnt Ac-S DC cascade configuration
Host operations are transferred to the Cnt Ac-S secondary volume (S-VOL) at the intermediate site
when a disaster or failure occurs in the local site of a 3DC cascade configuration. The local site
failure is corrected and brought back online, then either the cascade configuration is restored or
the multi-target configuration is created.
See “3DC cascade configuration ” (page 124) for information and illustrations on the configuration
covered in this procedure.
Procedure 33 To recover a 3DC cascade configuration failure
1. Check consistency of the secondary volume in the intermediate site.
2. Run the horctakeover command on the secondary volume.
3. Wait until the secondary volume in the intermediate site is suspended (in SSWS status) or
changes to a primary volume, then use the volume to resume host operations.
Recovery for 3 Cnt Ac-J/Cnt Ac-S data centers 89