VERITAS Volume Manager 3.5 Administrator's Guide (September 2004)

Chapter 2 69
• simple—the public and private regions are on the same disk area
(with the public area following the private area). Typically, most or
all disks on your system are configured as this disk type.
• nopriv—there is no private region (only a public region for allocating
subdisks).
This is the simplest disk type consisting only of space for allocating
subdisks. Nopriv disks are most useful for defining special devices
(such as RAM disks, if supported) on which private region data
would not persist between reboots. They can also be used to
encapsulate disks where there is insufficient room for a private
region. Such disks cannot store configuration and log copies, and
they do not support the use of the vxdisk addregion command to
define reserved regions. VxVM cannot track the movement of nopriv
disks on a SCSI chain or between controllers.
On some systems, VxVM asks the operating system for a list of known
disk device addresses. These device addresses are auto-configured into
the rootdg disk group when vxconfigd is started. Auto-configured disks
are always of type simple, with default attributes.
For more information about disk types and their configuration, see the
vxdisk(1M) manual page.
Metadevices
Two classes of disk device files can be used with VxVM: standard devices,
and special devices known as metadevices. Metadevices are only used
with operating systems that support dynamic multipathing (DMP). Such
devices represent the physical disks that a system can access via more
than one physical path. The available access paths depend on whether
the disk is a single disk, or part of a multiported disk array that is
connected to a system.
You can use the vxdisk utility to display the paths subsumed by a
metadevice, and to display the status of each path (for example, whether
it is enabled or disabled). For more information, see “Administering
Dynamic Multipathing (DMP)” on page 105.