HP EVA P6550 HP P6300/P6500 EVA User Guide (5697-2486, September 2013) - Page 307

port port-colored port_name power distribution module power distribution unit power supply preferred address preferred path protocol pushbutton A physical connection that allows data to pass between a host and a disk array. Pertaining to the application of the color of port or red wine to a CRU tab, lever, or handle to identify the unit as hot-pluggable. A 64-bit unique identifier assigned to each Fibre Channel port. The port_name is communicated during the login and port discovery processes. See PDM. See PDU. An element that develops DC voltages for operating the storage system elements from either an AC or DC source. An AL_PA which a node port attempts to acquire during loop initialization. A preference for which controller of the controller pair manages the virtual disk. This preference is set by the user when creating the virtual disk. A host can change the preferred path of a virtual disk at any time. The primary purpose of preferring a path is load balancing. The conventions or rules for the format and timing of messages sent and received. A button that is engaged or disengaged when it is pressed. Q quiesce The act of rendering bus activity inactive or dormant. For example, "quiesce the SCSI bus operations during a device warm-swap." R rack rack-mounting unit read ahead caching read caching reconstruction redundancy A floorstanding structure primarily designed for, and capable of, holding and supporting storage system equipment. All racks provide for the mounting of panels per Electronic Industries Alliance (EIA) Standard RS310C. A measurement for rack heights based upon a repeating hole pattern. It is expressed as "U" spacing or panel heights. Repeating hole patterns are spaced every 44.45 mm (1.75 inches) and based on EIA's Standard RS310C. For example, a 3U unit is 133.35 mm (5.25 inches)high, and a 4U unit is 177.79 mm (7.0 inches) high. A cache management method used to decrease the subsystem response time to a read request by allowing the controller to satisfy the request from the cache memory rather than from the disk drives. A cache method used to decrease subsystem response times to a read request by allowing the controller to satisfy the request from the cache memory rather than from the disk drives. Reading data from cache memory is faster than reading data from a disk. The read cache is specified as either On or Off for each virtual disk. The default state is on. The process of regenerating the contents of a failed member data. The reconstruction process writes the data to a spare set disk and incorporates the spare set disk into the mirrorset, striped mirrorset or RAID set from which the failed member came. 1. Element Redundancy-The degree to which logical or physical elements are protected by having another element that can take over in case of failure. For example, each loop of a device-side loop pair normally works independently but can take over for the other in case of failure. 2. Data Redundancy-The level to which user data is protected. Redundancy is directly proportional to cost in terms of storage usage; the greater the level of data protection, the more storage space is required. 307