Compaq HSZ80 manual RAIDset

	GL–13
RAID level 3/5	A Compaq-developed RAID storageset that stripes data and parity across
	three or more members in a disk array. A RAIDset combines the best
	characteristics of RAID level 3 and RAID level 5. A RAIDset is the best
	choice for most applications with small to medium I/O requests, unless the
	application is write intensive. A RAIDset is sometimes called parity RAID.
	Raid level 3/5 storagesets are sometimes referred to as RAIDsets.
RAIDset	See RAID level 3/5.
read-ahead caching	A caching technique for improving performance of synchronous sequential
	reads by prefetching data from disk.
read caching	A cache management method used to decrease the subsystem’s response
	time to a read request by allowing the controller to satisfy the request from
	the cache memory rather than from the disk drives.
reconstruction	The process of regenerating the contents of a failed member’s data. The
	reconstruct process writes the data to a spareset disk and then incorporates
	the spareset disk into the mirrorset, striped mirrorset, or RAIDset from
	which the failed member came. See also regeneration.
reduced	Indicates that a mirrorset or RAIDset is missing one member because the
	member has failed or has been physically removed.
redundancy	The provision of multiple interchangeable components to perform a single
	function in order to cope with failures and errors. A RAIDset is considered
	to be redundant when all of the parity blocks contain the correct parity for
	the user data.
regeneration	(1) The process of calculating missing data from redundant data. (2) The
	process of recreating a portion of the data from a failing or failed drive using
	the data and parity information from the other members within the
	storageset. The regeneration of an entire RAIDset member is called
	reconstruction. See also reconstruction.
request rate	The rate at which requests are arriving at a servicing entity.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide