Failure of a storage system, Failure of a primary system, Failure of a backup system – HP 3PAR Operating System Software User Manual
Page 159: Write errors, Write errors on the primary system, Write errors on the backup system
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 (see
).
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
the following:
•
“Changing Secondary Volume Groups to Primary” (page 117)
•
“Recovering from Disaster” (page 162)
Failure of a Backup System
When a backup system in a remote-copy pair fails, HP 3PAR Remote Copy handles the failure like
a failure of all links (see
).
For information about restarting and resynchronizing the volume groups after you recover the
backup system, see the following:
•
“Restarting Synchronous Volume Groups after Link Recovery” (page 158)
•
“Resynchronizing Asynchronous Periodic Volume Groups after Link Recovery” (page 158)
Write Errors
Write Errors on the Primary System
When a write error occurs on the primary system, regardless of the volume group mode, 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, HP 3PAR Remote Copy handles the error based on volume group mode.
For more information about volume group modes, see
“Volume Group Modes” (page 120)
Write Errors for Synchronous and Asynchronous Periodic Volume Groups
When a write error occurs on the backup system:
•
Host I/O completes without error when it is a synchronous volume group. (This does not apply
to asynchronous periodic volume groups, because host I/O has already been acknowledged
on the primary before backup asynchronous periodic volume groups are synchronized.)
•
HP 3PAR Remote Copy stops replication for the volume group.
•
HP 3PAR Remote Copy creates snapshots of each virtual volume in the volume group.
•
HP 3PAR Remote Copy generates an alert indicating that an I/O error has occurred on the
backup system and specifying the volume group that is stopped as a result.
HP 3PAR Remote Copy does not automatically restart replication that is stopped as a result of write
errors. Even if the auto_recover policy is set, it automatically restarts only replication that is
stopped as a result of link failure.
To restart a synchronous volume group that stopped after a write error, issue the startrcopygroup
command on the primary system after addressing the issue that caused the write error.
Failure of a Storage System
159