Volume Sets
The VERITAS Volume Manager exports a feature called volume sets. Unlike the traditional Volume Manager volume, which can be used for raw I/O access or to contain a file system, a volume set is a container for multiple different volumes. Each volume can have its own geometry.
The Volume Manager vxvset command is used to create and manage volume sets. For example, the following command creates a new volume set from an existing volume named vol1:
# vxvset make myvset vol1
The following commands create two new volumes and add them to the volume set:
# vxassist make vol2 50m
# vxassist make vol3 50m
# vxvset addvol myvset vol2
# vxvset addvol myvset vol3
The following command lists the component volumes of the previously created volume set:
# vxvset list myvset
VOLUME INDEX LENGTH STATE CONTEXT
vol1 0 20480 ACTIVE -
vol2 1 102400 ACTIVE -
vol3 2 102400 ACTIVE -
When a volume set is created, the volumes contained by the volume set are removed from the namespace and are instead accessed through the volume set name, as shown by the output of the ls command:
# ls -l /dev/vx/rdsk/rootdg/myvset
1 root root 108,70009 May 21 15:37 /dev/vx/rdsk/rootdg/myvset
However, when a volume is added to the volume set, it is no longer visible in the namespace, as shown in the following example:
# vxassist make vol4 50m
# ls -l /dev/vx/rdsk/rootdg/vol4
crw-- 1 root root 108,70012 May 21 15:43 /dev/vx/rdsk/rootdg/vol4
# vxvset addvol myvset vol4
# ls -l /dev/vx/rdsk/rootdg/vol4
/dev/vx/rdsk/rootdg/vol4: No such file or directory
Volume sets cannot be empty, so when the last entry is removed, the volume set itself is removed.
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