VERITAS Volume Manager 3.1 Administrator's Guide

Recovery
Miscellaneous RAID-5 Operations
Chapter 8 381
contents of the volume unusable. It is therefore not recommended.
Step 2. Any existing logging plexes are zeroed and enabled. If all logs fail during
this process, the start process is aborted.
Step 3. If no stale subdisks exist or those that exist are recoverable, the volume
is put in the ENABLED kernel state and the volume state is set to
ACTIVE. The volume is now started.
Step 4. 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.
Step 5. 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 do
not stop the start procedure.