Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

Adding a RAID-5 log using vxplex
You can also add a RAID-5 log using the vxplex command. For example, to attach
the RAID-5 log plex r5log, to the RAID-5 volume r5vol, in the disk group mydg,
use the following command:
# vxplex -g mydg att r5vol r5log
The attach operation can only proceed if the size of the new log is large enough
to hold all the data on the stripe. If the RAID-5 volume already contains logs, the
new log length is the minimum of each individual log length. The reason is that
the new log is a mirror of the old logs.
If the RAID-5 volume is not enabled, the new log is marked as BADLOG and is
enabled when the volume is started. However, the contents of the log are ignored.
If the RAID-5 volume is enabled and has other enabled RAID-5 logs, the new log’s
contents are synchronized with the other logs.
If the RAID-5 volume currently has no enabled logs, the new log is zeroed before
it is enabled.
Removing a RAID-5 log
To identify the plex of the RAID-5 log, use the following command:
# vxprint [-g diskgroup] -ht volume
where volume is the name of the RAID-5 volume. For a RAID-5 log, the output
lists a plex with a STATE field entry of LOG.
To dissociate and remove a RAID-5 log and any associated subdisks from an
existing volume, use the following command:
# vxplex [-g diskgroup] -o rm dis plex
For example, to dissociate and remove the log plex volraid-02 from volraid in
the disk group mydg, use the following command:
# vxplex -g mydg -o rm dis volraid-02
You can also remove a RAID-5 log with the vxassist command, as follows:
# vxassist [-g diskgroup] remove log volume [nlog=n]
By default, the vxassist command removes one log. To specify the number of
logs that remain after the operation, use the optional attribute nlog=n.
383Administering volumes
Adding a RAID-5 log