Operating System Software Owner manual

Link Failure and Asynchronous Periodic Volume Groups
For asynchronous periodic volume groups, when all links between a Remote Copy pair fail:
• Remote Copy stops replication on both storage systems.
• Remote Copy does not create any new snapshots.
• If a resynchronization was in progress when the failure occurred, Remote Copy automatically
promotes the pre-existing snapshots on the secondary volume group—but only for those volumes
that did not complete resynchronization.
For more information, see “Snapshots and Resynchronization Failure” (page 206).
Resyncing Asynchronous Periodic Volume Groups after Link Recovery
For asynchronous periodic groups, when the links are restored:
• To restart replication between volume groups, issue the startrcopygroup command.
Remote Copy resynchronizes the virtual volumes at the next scheduled resynchronization time.
• To immediately resynchronize the volume groups, issue the syncrcopy command.
Failure of a Storage System
If one of the systems in a Remote Copy pair fails, the other system:
• detects the failure as a concurrent failure of both communication links
• generates an alert
• handles the failure like a “Failure of All Links” (page 208)
Failure of a Primary System
When a primary system fails and you need access to the data on the secondary virtual volumes,
you must switch the role of the volume groups containing those volumes. For more information,
see:
• “Changing Secondary Volume Groups to Primary” (page 93)
• “Recovering from Disaster” (page 102)
Failure of a Backup System
When a backup system in a Remote Copy pair fails, Remote Copy handles the failure like a “Failure
of All Links” (page 208).
For information about restarting and resyncing the volume groups after you recover the backup
system, see:
• “Restarting Synchronous Volume Groups after Link Recovery” (page 208)
• “Resyncing Asynchronous Periodic Volume Groups after Link Recovery” (page 209)
Write Errors
Write Errors on the Primary System
When a write error occurs on the primary system, the system returns the error to the host as an
I/O failure.
Write Errors on the Backup System
If a write completes successfully on the primary system but a write error occurs on the backup
system, Remote Copy handles the error based on volume group mode.
Failure of a Storage System 209