Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

212 Creating and administering subdisks
Dissociating subdisks from plexes
# 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] [-o force] 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 removing the subdisk
makes the volume unusable, because another subdisk in the same stripe is unusable or
missing and the volume is not DISABLED and empty, the operation is not allowed.
Removing subdisks
To remove a subdisk, use the following command:
# vxedit [-g diskgroup] rm subdisk
For example, to remove a subdisk named mydg02-01 from the disk group, mydg, use
the following command:
# vxedit -g mydg rm mydg02-01