Dot Hill Systems 200 manual Nvram, Pid, Raid, Ras, Rdac, Saf-Te, San

	commission to complete a repair process.
N port	A Fibre Channel port in a point-to-point or Fabric connection.
NVRAM	Non-Volatile Random Access Memory. A memory unit equipped with a battery so that the
	data stays intact even after the main power had been switched off.
out-of-band	Refers to the connections and devices that are not in the data path.
parity	Additional information stored along with the data that allows the controller to reconstruct
	lost data on RAID 3 or 5 LUNs if a single drive fails.
parity check	A process whereby the integrity of the redundant data on fault tolerant arrays (RAID 1, 3,
	5, and 6 or 1+0) is checked. The parity checking procedure on a logical drive recalculates
	the parity of data stripes in each of the logical drive's RAID stripe sets and compares it
	with the stored parity. If a discrepancy is found, an error will be reported and the new
	correct parity will be substituted for the stored parity.
partner group	A pair of interconnected controller units. Expansion units interconnected to the pair of
	controller units can also be part of the partner group.
physical array	A physical array is a group of physical drives in SANscape that participate in one or more
	logical drives. If a group of physical drives is configured into a logical drive without using
	the entire capacity of the physical drives, SANscape will require that the same physical
	array of drives be used together in any remaining logical drives that are created with the
	remaining capacity. In the New Configuration window, the Add Disk button changes
PID	Primary controller identifier number
RAID	Redundant Array of Independent Disks. An arrangement of two or more disk drives
	configured to work together to provide more disk storage space, better performance,
	and/or redundant backup of data. Defined RAID levels describe various combinations of
	these features.
RAID controller	An enclosure containing one or two RAID controllers, a group of drives, power supplies,
drive array	cooling fans, I/O cards, and mid-planes.
RAS	Reliability, availability, and serviceability. Features that enhance these attributes,
	including hot-pluggable capability and redundancy, are important for keeping mission-
	critical applications and data on-line.
RDAC	Redundant disk array controller. The RDAC driver is included in the RAID Manager
	software, and manages the rerouting of active I/O operations when a controller fails.
read policy	Descriptions of the read policies are as follows: When you indicate a No Cache read
	policy, the controller will not store data in the read cache. Normal specifies that the
	current controller does not use Read ahead caching for the current drive. Set the read
	policy to Read Ahead and the controller will read multiple adjacent blocks of data
	automatically. This is most effective for applications with sequential reads.
rebuild	Rebuilding a disk is the process of reconstructing the data on a disk before it failed.
	Rebuilding can be done only in arrays with data redundancy, such as RAID levels 1, 3, 5
	or 1+0. See "automatic rebuild" on page -3 for detailed information on rebuilding. For the
	Rebuild rate, refer to "background rate."
reconstruction	Process used to restore a degraded RAID 1, 3, or 5 LUN to its original state after replacing
	a single failed drive.
S.M.A.R.T.	Self-Monitoring Analysis and Reporting Technology. The industry standard reliability
	prediction indicator for both the IDE/ATA and SCSI hard disk drives. Hard disk drives
	with SMART offer early warning of some hard disk failures so critical data can be
	protected.
SAF-TE	SCSI Accessed Fault-Tolerant Enclosures.
SAN	Storage Area Networking. A high-speed, open-standard scalable network of storage
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