Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

101Administering disks
Rootability
VxVM root disk volume restrictions
Volumes on a bootable VxVM root disk have the following configuration restrictions:
■ All volumes on the root disk must be in the disk group that you choose to be the
bootdg disk group.
■ The names of the volumes with entries in the LIF LABEL record must be
standvol, rootvol, swapvol, and dumpvol (if present). The names of the
volumes for other file systems on the root disk are generated by appending vol to
the name of their mount point under /.
■ Any volume with an entry in the LIF LABEL record must be contiguous. It can have
only one subdisk, and it cannot span to another disk.
■ The rootvol and swapvol volumes must have the special volume usage types
root and swap respectively.
■ Only the disk access types auto with format hpdisk, and simple are suitable for
use as VxVM root disks, root disk mirrors, or as hot-relocation spares for such disks.
An auto-configured cdsdisk format disk, which supports the Cross-platform Data
Sharing (CDS) feature, cannot be used. The
vxcp_lvmroot and vxrootmir
commands automatically configure a suitable disk type on the physical disks that you
specify are to be used as VxVM root disks and mirrors.
■ The volumes on the root disk cannot use dirty region logging (DRL).
In addition, the size of the private region for disks in a VxVM boot disk group is limited to
1MB, rather than the usual default value of 32MB. This restriction is necessary to allow
the boot loader to find the /stand file system during Maintenance Mode Boot.
Root disk mirrors
All the volumes on a VxVM root disk may be mirrored. The simplest way to achieve this
is to mirror the VxVM root disk onto an identically sized or larger physical disk. If a
mirror of the root disk must also be bootable, the restrictions listed in “Booting root
volumes” on page 101 also apply to the mirror disk.
Note: If you mirror only selected volumes on the root disk and use spanning or striping to
enhance performance, these mirrors are not bootable.
See “Setting up a VxVM root disk and mirror” on page 102 for details of how to create a
mirror of a VxVM root disk.