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Apple Xsan 1.4 User Manual

Page 186

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186

Glossary

RAID array A group of physical disks organized and protected by a RAID scheme and

presented by RAID hardware or software as a single logical disk. In Xsan, RAID arrays

appear as LUNs, which are combined to form storage pools.

round robin An Xsan storage pool allocation strategy. In a volume consisting of more

than one storage pool, Xsan allocates space for successive writes to each available pool

in turn.

SAN Storage area network. In general, a network whose primary purpose is the

transfer of data between computer systems and storage elements and among storage

elements. In Xsan, a SAN is a combination or one or more controllers, storage volumes,

and storage clients.

storage pool A group of logical disks that share common characteristics, such as

throughput or latency, across which user data is striped. In Xsan, storage pools are

combined into volumes. ADIC’s StorNext File System calls this a stripe group.

stripe breadth An Xsan storage pool property. The number of bytes of data, expressed

as a number of file system blocks, that Xsan writes to a LUN in a storage pool before

moving to the next LUN in the pool.

stripe group The StorNext File System term for an Xsan storage pool.

volume A mountable allocation of storage that behaves, from the client’s perspective,

like a local hard disk, hard disk partition, or network volume. In Xsan, a volume consists

of one or more storage pools. See also logical disk.