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

Chapter 8, Administering Volumes
Adding a RAID-5 Log
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Once created, the plex containing a log subdisk can be treated as a regular plex. Data
subdisks can be added to the log plex. The log plex and log subdisk can be removed using
the procedure described in “Removing a Traditional DRL Log” on page 243.
Removing a Traditional DRL Log
Note The procedure described in this section removes a DRL log that is configured within
a dedicated DRL plex. The version 20 DCO volume layout includes space for a DRL
log.
To remove a DRL log, use the vxassist command as follows:
# vxassist [-g diskgroup] remove log volume logtype=drl [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.
You can use storage attributes to specify the storage from which a log is to be removed.
For example, to remove a log on disk mydg10 from volume vol01, enter:
# vxassist -g mydg remove log vol01 !mydg10 logtype=drl
Adding a RAID-5 Log
Note You need a full license to use this feature.
Only one RAID-5 plex can exist per RAID-5 volume. Any additional plexes become
RAID-5 log plexes, which are used to log information about data and parity being written
to the volume. When a RAID-5 volume is created using the vxassist command, a log
plex is created for that volume by default.
To add a RAID-5 log to an existing volume, use the following command:
# vxassist [-b] [-g diskgroup] addlog volume [loglen=length]
Note If specified, the -b option makes adding the new log a background task.
You can specify the log length used when adding the first log to a volume. Any logs
that you add subsequently are configured with the same length as the existing log.
For example, to create a log for the RAID-5 volume volraid, in the disk group, mydg, use
the following command:
# vxassist -g mydg addlog volraid