HP 12000 HP StorageWorks 12000 Gateway Virtual Library System User Guide (AH81 - Page 251

infrastructure The physical hardware used to interconnect computers. Infrastructure also includes the software used to send, receive, and manage the signals that are transmitted. initiator A media (host) server that runs the backup/restore application that passes commands and data between the network and the VLS. inputs/outputs per A performance measurement for a host-attached storage device or RAID controller. second library logical unit number (LUN) LUN mapping LUN masking A storage device that handles multiple units of media and provides one or more drives for reading and writing them, such as a physical tape library and virtual tape library. Software emulation of a physical tape library is called a virtual tape library. An address used in the SCSI protocol to access a device within a target. In the case of the VLS, a LUN is assigned to each virtual library and tape drive. A mechanism of changing the LUN assignments for a specific host. An authorization process that makes a LUN available to some hosts and unavailable to other hosts. mean time until data loss (MTDL) media access control (MAC) address media server The average time until a component failure can be expected to cause data loss. This includes the consideration that RAID redundancy can protect against data loss from the failure of a single component. A low-level unique hardware identifier for every Ethernet port in the world that is physically stored inside a network card or similar network interface. MAC addresses are assigned by the IEEE. A computer whose purpose is to move or copy data from one location to another, such as from network clients to tape cartridges in a library. node A server that contains the hardware and firmware required to run a virtual library system. This refers to a hardware assembly containing a power supply, cooling fans, motherboard, expansion boards, and internal hard drives to support the VLS system. oversubscription A condition that exists when more virtual media storage is configured on a VLS than there is physical storage available. Because the VLS dynamically allocates storage space as user data is written, the VLS allows you to allocate more storage for virtual media than is physically available. port mapping primary node A mechanism of assigning a LUN (virtual device), such as a virtual library or tape drive, to a specific FC host port. Port mapping allows you to load-balance the LUNs among the FC host ports to maximize bandwidth. At this time, you must manually load-balance the virtual tape drives in a VLS. A computer (node) that provides primary administrating and control for backup and restore operations on a server cluster and provides communication and control for all secondary servers on the system. RAID A RAID volume consists of more than one drive, but appears to the operating system to be a single logical disk. RAID improves performance by disk striping, which involves partitioning each drive's storage space into units. By placing data HP StorageWorks 12000 Gateway Virtual Library System User Guide 251