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

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] [-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
Warning: 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.
Creating and administering subdisks and plexes
Dissociating subdisks from plexes
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