This type of multi-pathed disk array allows you to access a disk in the disk array through all the paths to the disk simultaneously, without any performance degradation.

This type of multipathed disk array allows one path to a disk to be designated as primary and used to access the disk at any time. Using a path other than the designated active path results in severe performance degradation in some disk arrays.

The device name or address used to access a physical disk, such as sda or sda3, where sda indicates the whole device, and sda3 refers to the third partition on sda.

In a SAN environment, it is more convenient to use enclosure-based naming, which forms the device name by concatenating the name of the enclosure (such as enc0) with the disk's number within the enclosure, separated by an underscore (for example, enc0_2). The term disk access name can also be used to refer to a device name.

A path to a disk that is not available for I/O. A path can be disabled due to real hardware failures or if the user has used the vxdmpadm disable command on that controller.

A collection of read/write data blocks that are indexed and can be accessed fairly quickly. Each disk has a universally unique identifier.

An alternative term for a device name.

A collection of disks logically arranged into an object. Arrays tend to provide benefits such as redundancy or improved performance.

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.

In the multi-pathing 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.

An intelligent disk array that usually has a backplane with a built-in Fibre Channel loop, and which permits hot-swapping of disks.

A universally unique identifier that is given to each disk and can be used to identify the disk, even if it is moved.

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.

A path to a disk that is available for I/O.

See disk enclosure.

See device name.

A disk device that is accessible on a Storage Area Network (SAN) via a Fibre Channel switch.

A collective name for the fiber optic technology that is commonly used to set up a Storage Area Network (SAN).

A collection of files organized together into a structure. The UNIX file system is a hierarchical structure consisting of directories and files.

Where there are multiple physical access paths to a disk connected to a system, the disk is called multi-pathed. Any software residing on the host, (for example, the DMP driver) that hides this fact from the user is said to provide multi-pathing functionality.

When a disk is connected to a host, the path to the disk consists of the HBA (Host Bus Adapter) on the host, the SCSI or fibre cable connector and the controller on the disk or disk array. These components constitute a path to a disk. A failure on any of these results in DMP trying to shift all I/O for that disk onto the remaining (alternate) paths.

In Active/Passive disk arrays, a disk can be bound to one particular controller on the disk array or owned by a controller. The disk can then be accessed using the path through this particular controller.

A disk array set up with part of the combined storage capacity used for storing duplicate information about the data stored in that array. This makes it possible to regenerate the data if a disk failure occurs.

In Active/Passive disk arrays, the paths to a disk other than the primary path are called secondary paths. A disk is supposed to be accessed only through the primary path until it fails, after which ownership of the disk is transferred to one of the secondary paths.

A networking paradigm that provides easily reconfigurable connectivity between any subset of computers, disk storage and interconnecting hardware such as switches, hubs and bridges.

The storage area that is assigned to a virtual machine.

The storage pool consisting of the Solid-State Drives (SSDs), Hard Disk Drives (HDD), and other local data storage devices attached to hosts that are claimed by Veritas DMP. SmartPool provides a caching storage for virtual machines running Symantec Storage Foundation's SmartIO solution.