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

Understanding VERITAS Volume Manager
Device Discovery
Chapter 112
NOTE Even though rootdg is the default disk group, it does not necessarily
contain the root disk. In the current release, the root disk may be under
VxVM or LVM control.
You can create additional disk groups as necessary. Disk groups allow
you to group disks into logical collections. A disk group and its
components can be moved as a unit from one host machine to another.
The ability to move whole volumes and disks between disk groups, to
split whole volumes and disks between disk groups, and to join disk
groups is described in “Reorganizing the Contents of Disk Groups” on
page 152.
Volumes are created within a disk group. A given volume must be
configured from disks in the same disk group.
Subdisks
A subdisk is a set of contiguous disk blocks. A block is a unit of space on
the disk. VxVM allocates disk space using subdisks. A VM disk can be
divided into one or more subdisks. Each subdisk represents a specific
portion of a VM disk, which is mapped to a specific region of a physical
disk.
The default name for a VM disk is disk## (such as disk01) and the
default name for a subdisk is disk##-##. In the figure, “Subdisk
Example,”, disk01-01 is the name of the first subdisk on the VM disk
named disk01.
Figure 1-6 Subdisk Example
SubdiskVM Disk with One Subdisk
disk01-01 disk01-01
disk01