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

Understanding VERITAS Volume Manager
Device Discovery
Chapter 1 13
A VM disk can contain multiple subdisks, but subdisks cannot overlap or
share the same portions of a VM disk. Figure 1-7, “Example of Three
Subdisks Assigned to One VM Disk,” shows a VM disk with three
subdisks. The VM disk is assigned to one physical disk.
Figure 1-7 Example of Three Subdisks Assigned to One VM Disk
Any VM disk space that is not part of a subdisk is free space. You can use
free space to create new subdisks.
VxVM release 3.0 or higher supports the concept of layered volumes in
which subdisks can contain volumes. For more information, see “Layered
Volumes” on page 35.
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 Figure 1-8, “Example of a Plex
with Two Subdisks,”
Figure 1-8 Example of a Plex with Two Subdisks
You can organize data on subdisks to form a plex by using the following
methods:
VM DiskPhysical Disk Subdisks
devname
disk01
disk01-01
disk01-02
disk01-03
disk01-01
disk01-02
disk01-03
disk01
vol01-01
disk01-01
disk01-02
disk01-01
disk01-02
Plex
Subdisks