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

509Glossary
disk
A collection of read/write data blocks that are indexed and can be accessed fairly quickly. Each disk
has a universally unique identifier.
disk access name
An alternative term for a device name.
disk access records
Configuration records used to specify the access path to particular disks. Each disk access record
contains a name, a type, and possibly some type-specific information, which is used by VxVM in
deciding how to access and manipulate the disk that is defined by the disk access record.
disk array
A collection of disks logically arranged into an object. Arrays tend to provide benefits such as
redundancy or improved performance. Also see disk enclosure and JBOD.
disk array serial number
This is the serial number of the disk array. It is usually printed on the disk array cabinet or can be
obtained by issuing a vendor- specific SCSI command to the disks on the disk array. This number is
used by the DMP subsystem to uniquely identify a disk array.
disk controller
In the multipathing subsystem of VxVM, the controller (host bus adapter or HBA) or disk array
connected to the host, which the operating system represents as the parent node of a disk.
disk enclosure
An intelligent disk array that usually has a backplane with a built-in Fibre Channel loop, and which
permits hot-swapping of disks.
disk group
A collection of disks that share a common configuration. A disk group configuration is a set of
records containing detailed information on existing VxVM objects (such as disk and volume
attributes) and their relationships. Each disk group has an administrator-assigned name and an
internally defined unique ID. The disk group names bootdg (an alias for the boot disk group),
defaultdg (an alias for the default disk group) and nodg (represents no disk group) are reserved.
disk group ID
A unique identifier used to identify a disk group.
disk ID
A universally unique identifier that is given to each disk and can be used to identify the disk, even if it
is moved.
disk media name
An alternative term for a disk name.
disk media record
A configuration record that identifies a particular disk, by disk ID, and gives that disk a logical (or
administrative) name.
disk name
A logical or administrative name chosen for a disk that is under the control of VxVM, such as
disk03. The term disk media name is also used to refer to a disk name.