Veritas Volume Manager 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

Adding a RAID-5 Log
244 VERITAS Volume Manager Administrator’s Guide
Adding a RAID-5 Log using vxplex
As an alternative to using vxassist, you can add a RAID-5 log using the vxplex
command. For example, to attach a RAID-5 log plex, r5log, to a 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
of 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. This is because 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. Use the optional attribute nlog=n
to specify the number of logs that are to remain after the operation completes.