VERITAS Volume Manager 3.5 Administrator's Guide (September 2004)

Understanding VERITAS Volume Manager
Device Discovery
Chapter 114
• concatenation
• striping (RAID-0)
• mirroring (RAID-1)
• striping with parity (RAID-5)
Concatenation, striping (RAID-0), mirroring (RAID-1) and RAID-5 are
described in “Volume Layouts in VxVM” on page 17.
Volumes
A volume is a virtual disk device that appears to applications, databases,
and file systems like a physical disk device, but does not have the
physical limitations of a physical disk device. A volume consists of one or
more plexes, each holding a copy of the selected data in the volume. Due
to its virtual nature, a volume is not restricted to a particular disk or a
specific area of a disk. The configuration of a volume can be changed by
using VxVM user interfaces. Configuration changes can be accomplished
without causing disruption to applications or file systems that are using
the volume. For example, a volume can be mirrored on separate disks or
moved to use different disk storage.
NOTE VxVM uses the default naming conventions of vol## for volumes and
vol##-## for plexes in a volume. For ease of administration, you can
choose to select more meaningful names for the volumes that you create.
A volume may be created under the following constraints:
• Its name can contain up to 31 characters.
• It can consist of up to 32 plexes, each of which contains one or more
subdisks.
• It must have at least one associated plex that has a complete copy of
the data in the volume with at least one associated subdisk.
• All subdisks within a volume must belong to the same disk group.