VERITAS Volume Manager 3.5 Administrator's Guide (September 2002)

Chapter 2, Administering Disks
Disk Devices
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◆ Disks in the DISKS category (formerly known as JBOD disks) are named using the
Disk_# format.
◆ Disks in the OTHER_DISKS category 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 61 for details of how to switch
between the two naming schemes.
To display the native OS device names of a VM disk (such as disk01), use the following
command:
# vxdisk list diskname
For information on how to rename an enclosure, see “Renaming an Enclosure” on
page 102.
Private and Public Disk Regions
A VM disk usually has two regions:
◆ private region—a small area where configuration information is stored. A disk header
label, configurationrecords forVxVM 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 130). If required, the value for the
private region size may be overridden at installation time by choosing the Custom
Installation path, or when you add or replace a disk using the vxdiskadm command.
Note Each disk that has a private region holds an entire copy of the configuration
database for the disk group. The size of the configuration database for a disk group
is limited by the size of the smallest copy of the configuration database on any of its
member disks.
◆ public region—an area that covers the remainder of the disk and is used to store
subdisks (and allocate storage space).
The following basic disk types are used by VxVM: