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

59
Administering Disks
2
This chapter describes the operations for managing disks used by the VERITAS Volume
Manager (VxVM). This includes placing disks under VxVM control, initializing disks,
mirroring the root disk, and removing and replacing disks.
Note Most VxVM commands require superuser or equivalent privileges.
Disks that are controlled by the LVM subsystem cannot be used directly as VxVM
disks, but they can be converted so that their volume groups and logical volumes
become VxVM disk groups and volumes. For more information on conversion, see
the VERITAS Volume Manager Migration Guide.
For information about configuring and administering the Dynamic Multipathing (DMP)
feature of VxVM that is used with multiported disk arrays, see “Administering Dynamic
Multipathing (DMP)” on page 101.
Disk Devices
When performing disk administration, it is important to understand the difference
between a disk name and a device name.
When a disk is placed under VxVM control, a VM disk is assigned to it. You can define a
symbolic disk name (also known as a disk media name) to refer to a VM disk for the purposes
of administration. A disk name can be up to 31 characters long. If you do not assign a disk
name, it defaults to diskgroup## where diskgroup is the name of the disk group to which
the disk is being added, and ## is a sequence number. Your system may use device names
that differ from those given in the examples.
The device name (sometimes referred to as devname or disk access name) defines the name of
a disk device as it is known to the operating system. Such devices are usually, but not
always, located in the /dev/[r]dsk directories. Devices that are specific to hardware
from certain vendors may use their own path name conventions.
VxVM recreates disk devices, including those from the /dev/[r]dsk directories, as
metadevices in the /dev/vx/[r]dmp directories. The dynamic multipathing (DMP)
feature of VxVM uses these metadevices (or DMP nodes) to represent disks that can be