Veritas Volume Manager 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

How VxVM Handles Storage Management
14 VERITAS Volume Manager Administrator’s Guide
Plexes
VxVM uses subdisks to build virtual objects called plexes. A plex consists of one or more
subdisks located on one or more physical disks. For example, see the plex vol01-01
shown in “Example of a Plex with Two Subdisks.”
Example of a Plex with Two Subdisks
You can organize data on subdisks to form a plex by using the following methods:
◆ 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.
vol01-01
Plex with Two Subdisks
Subdisks
disk01-01 disk01-02
disk01-01 disk01-02