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

Chapter 2, Administering Disks

Disk Devices

◆ All fabric or non-fabric disks in supported disk arrays are named using the

enclosure_name_# format. For example, disks in the supported disk array,

enggdept are named enggdept_0, enggdept_1, enggdept_2 and so on. (You can

use the vxdmpadm command to administer enclosure names. See “Administering

DMP Using vxdmpadm” on page 112 and the vxdmpadm(1M) manual page for more

information.)

◆ Disks in the DISKS category (JBOD disks) are named using the Disk_# format.

◆ Disks in the OTHER_DISKS category (disks that are not multipathed by DMP) are

named as follows:

◆ Non-fabric disks are named using the c#t#d# format.

◆ Fabric disks are named using the fabric_# format.

See “Changing the Disk-Naming Scheme” on page 72 for details of how to switch

between the two naming schemes.

To display the native OS device names of a VM disk (such as mydg01), use the following

command:

# vxdisk path | egrep diskname

For information on how to rename an enclosure, see “Renaming an Enclosure” on

page 127.

For a description of disk categories, see “Disk Categories” on page 64.

Private and Public Disk Regions

Most VM disks have two regions:

private region A small area where configuration information is stored. A disk header

label, configuration records for VxVM objects (such as volumes, plexes

and subdisks), and an intent log for the configuration database are stored

here. The default private region size is 2048 blocks (2048 kilobytes), which

is large enough to record the details of about 4000 VxVM objects in a disk

group.

Under most circumstances, the default private region size should be

sufficient. For administrative purposes, it is usually much simpler to

create more disk groups that contain fewer volumes, or to split large disk

groups into several smaller ones (as described in “Splitting Disk Groups”

on page 165). If required, the value for the private region size may be

overridden when you add or replace a disk using the vxdiskadm

command.