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

Dissociating Subdisks from Plexes
180 VERITAS Volume Manager Administrator’s Guide
Note Only one log subdisk can be associated with a plex. Because this log subdisk is
frequently written, care should be taken to position it on a disk that is not heavily
used. Placing a log subdisk on a heavily-used disk can degrade system
performance.
To add a log subdisk to an existing plex, use the following command:
# vxsd [-g diskgroup] aslog plex subdisk
where subdisk is the name to be used for the log subdisk. The plex must be associated
with a mirrored volume before dirty region logging takes effect.
For example, to associate a subdisk named mydg02-01 with a plex named vol01-02,
which is already associated with volume vol01 in the disk group, mydg, use the
following command:
# vxsd -g mydg aslog vol01-02 mydg02-01
You can also add a log subdisk to an existing volume with the following command:
# vxassist [-g diskgroup] addlog volume disk
This command automatically creates a log subdisk within a log plex on the specified disk
for the specified volume.
Dissociating Subdisks from Plexes
To break an established connection between a subdisk and the plex to which it belongs,
the subdisk is dissociated from the plex. A subdisk is dissociated when the subdisk is
removed or used in another plex. To dissociate a subdisk, use the following command:
# vxsd [-g diskgroup] dis subdisk
For example, to dissociate a subdisk named mydg02-01 from the plex with which it is
currently associated in the disk group, mydg, use the following command:
# vxsd -g mydg dis mydg02-01
You can additionally remove the dissociated subdisks from VxVM control using the
following form of the command:
# vxsd [-g diskgroup] -o rm dis subdisk
Caution If the subdisk maps a portion of a volume’s address space, dissociating it places
the volume in DEGRADED mode. In this case, the dis operation prints a
warning and must be forced using the -o force option to succeed. Also, if