VERITAS Volume Manager 4.1 Troubleshooting Guide

Recovery from Hardware Failure
Recovering from Incomplete Disk Group Moves
Chapter 128
# 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.