Veritas Volume Manager 5.0 Troubleshooting Guide Guide (September 2006)

25Recovery from hardware failure
Recovering from incomplete disk group moves
# vxmend [-g diskgroup] fix unstale subdisk
■ If some subdisks are stale and need recovery, and if valid logs exist, the volume is
enabled by placing it in the ENABLED kernel state and the volume is available for use
during the subdisk recovery. Otherwise, the volume kernel state is set to DETACHED
and it is not available during subdisk recovery.
This is done because if the system were to crash or the volume was ungracefully
stopped while it was active, the parity becomes stale, making the volume unusable. If
this is undesirable, the volume can be started with the -o unsafe start option.
Caution: The -o unsafe start option is considered dangerous, as it can make the
contents of the volume unusable. It is therefore not recommended.
■ The volume state is set to RECOVER and stale subdisks are restored. As the data on
each subdisk becomes valid, the subdisk is marked as no longer stale.
If any subdisk recovery fails and there are no valid logs, the volume start is aborted
because the subdisk remains stale and a system crash makes the RAID-5 volume
unusable. This can also be overridden by using the -o unsafe start option.
Caution: The -o unsafe start option is considered dangerous, as it can make the
contents of the volume unusable. It is therefore not recommended.
If the volume has valid logs, subdisk recovery failures are noted but they do not stop
the start procedure.
■ When all subdisks have been recovered, the volume is placed in the ENABLED kernel
state and marked as ACTIVE. It is now started.
Recovering from incomplete disk group moves
If the system crashes or a subsystem fails while a disk group move, split or join operation
is being performed, VxVM attempts either to reverse or to complete the operation when
the system is restarted or the subsystem is repaired. Whether the operation is reversed or
completed depends on how far it had progressed.
Automatic recovery depends on being able to import both the source and target disk
groups. If this is not possible (for example, if one of the disk groups has been imported on
another host), perform the following steps to recover the disk group:
1Use the
vxprint command to examine the configuration of both disk groups.
Objects in disk groups whose move is incomplete have their TUTIL0 fields set to
MOVE.
2 Enter the following command to attempt completion of the move:
# vxdg recover sourcedg