HP EVA P6550 HP P6300/P6500 EVA User Guide (5697-2486, September 2013) - Page 298

Glossary This glossary defines terms used in this guide or related to this product and is not a comprehensive glossary of computer terms. Symbols and numbers 3U A unit of measurement representing three "U" spaces. "U" spacing is used to designate panel or enclosure heights. Three "U" spaces is equivalent to 5.25 inches (133 mm). See also rack-mounting unit. µm A symbol for micrometer; one millionth of a meter. For example, 50 µm is equivalent to 0.000050 m. A active member of a virtual disk family adapter AL_PA allocation policy ALUA ambient temperature ANSI arbitrated loop arbitrated loop physical address arbitrated loop topology array array controller array controller failover array-based management A simulated disk drive created by the controllers as storage for one or more hosts. An active member of a virtual disk family is accessible by one or more hosts for normal storage. An active virtual disk member and its snapshot, if one exists, constitute a virtual disk family. An active member of a virtual disk family is the only necessary member of a virtual disk family. See also virtual disk , virtual disk copy, virtual disk family . See controller. Arbitrated loop physical address. A 1-byte value the arbitrated loop topology uses to identify the loop ports. This value becomes the last byte of the address identifier for each public port on the loop. Storage system rules that govern how virtual disks are created. Allocate Completely and Allocate on Demand are the two rules used in creating virtual disks. • Allocate Completely-The space a virtual disk requires on the physical disks is reserved, even if the virtual disk is not currently using the space. • Allocate on Demand-The space a virtual disk requires on the physical disks is not reserved until needed. Asymmetric logical unit access. Operating systems that support asymmetric logical unit access work with the EVA's active/active functionality to enable any virtual disk to be accessed through either of the array's two controllers. The air temperature in the area where a system is installed. Also called intake temperature or room temperature. American National Standards Institute. A non-governmental organization that develops standards (such as SCSI I/O interface standards and Fibre Channel interface standards) used voluntarily by many manufacturers within the United States. A Fibre Channel topology that links multiple ports (up to 126) together on a single shared simplex media. Transmissions can only occur between a single pair of nodes at any given time. Arbitration is the scheme that determines which node has control of the loop at any given moment. See AL_PA. See arbitrated loop. A synonym of storage array, storage system, and virtual array. A group of disks in one or more disk enclosures combined with controller software that presents disk storage capacity as one or more virtual disks. See controller. The process that takes place when one controller assumes the workload of a failed companion controller. A management structure in which HP P6000 Command View is installed on the management module within the EVA controller enclosure. 298 Glossary