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

■ The first volume (index 0) in a volume set must be larger than the sum of the
total volume size divided by 4000, the size of the VxFS intent log, and 1MB.
Volumes 258 MB or larger should always suffice.
■ Raw I/O from and to a volume set is not supported.
■ Raw I/O from and to the component volumes of a volume set is supported
under certain conditions.
See “Raw device node access to component volumes” on page 389.
■ Resizing a volume set with an unmounted file system is not supported.
■ Volume sets can be used in place of volumes with the following vxsnap
operations on instant snapshots: addmir, dis, make, prepare, reattach,
refresh, restore, rmmir, split, syncpause, syncresume, syncstart, syncstop,
syncwait, and unprepare. The third-mirror break-off usage model for full-sized
instant snapshots is supported for volume sets provided that sufficient plexes
exist for each volume in the volume set.
For more information about snapshots, see the Veritas Storage Foundation
Advanced Features Administrator's Guide.
■ A full-sized snapshot of a volume set must itself be a volume set with the same
number of volumes and the same volume index numbers as the parent. The
corresponding volumes in the parent and snapshot volume sets are also subject
to the same restrictions as apply between standalone volumes and their
snapshots.
Creating a volume set
To create a volume set for use by Veritas File System (VxFS), use the following
command:
# vxvset [-g diskgroup] -t vxfs make volset
volume
Here volset is the name of the volume set, and volume is the name of the first
volume in the volume set. The -t vxfs option creates the volume set configured
for use by VxFS. You must create the volume before running the command. vxvset
will not automatically create the volume.
For example, to create a volume set named myvset that contains the volume vol1,
in the disk group mydg, you would use the following command:
# vxvset -g mydg -t vxfs make myvset vol1
Creating and administering volume sets
Creating a volume set
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