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

Specification of disk groups to commands
Many VxVM commands let you specify a disk group using the -g option. For
example, the following command creates a volume in the disk group, mktdg:
# vxassist -g mktdg make mktvol 5g
The block special device that corresponds to this volume is
/dev/vx/dsk/mktdg/mktvol.
System-wide reserved disk groups
The following disk group names are reserved, and cannot be used to name any
disk groups that you create:
Specifies the boot disk group. This is an alias for the disk group that
contains the volumes that are used to boot the system. VxVM sets
bootdg to the appropriate disk group if it takes control of the root
disk. Otherwise, bootdg is set to nodg (no disk group).
bootdg
Specifies the default disk group. This is an alias for the disk group
name that should be assumed if the -g option is not specified to a
command, or if the VXVM_DEFAULTDG environment variable is
undefined. By default, defaultdg is set to nodg (no disk group).
defaultdg
Specifies to an operation that no disk group has been defined. For
example, if the root disk is not under VxVM control, bootdg is set to
nodg.
nodg
Warning: Do not try to change the assigned value of bootdg. If you change the
value, it may render your system unbootable.
If you have upgraded your system, you may find it convenient to continue to
configure a disk group named rootdg as the default disk group (defaultdg).
defaultdg and bootdg do not have to refer to the same disk group. Also, neither
the default disk group nor the boot disk group have to be named rootdg.
Rules for determining the default disk group
You should use the -g option to specify a disk group to VxVM commands that
accept this option. If you do not specify the disk group, VxVM applies rules in the
following order until it determines a disk group name:
Creating and administering disk groups
About disk groups
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