HP NetRAID 1Si Controller - Manual (Page 154)

Glossary
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Rebuild Rate: The speed at which a rebuild operation occurs. Each HP NetRAID
Series adapter or integrated HP NetRAID controller is assigned a rebuild rate,
which specifies the percentage of processor resources to be devoted to rebuild
operations.
Reconstruct: The act of remaking a logical drive after changing RAID levels.
Redundancy: The provision of multiple interchangeable components to perform a
single function to cope with failures and errors. Redundancy normally applies to
hardware, such as using two or even three computers to do the same job. The
computers could all be active all the time, thus giving extra performance through
parallel processing and extra availability. Another type of redundancy is for one
computer to be active while the others monitor its activity, ready to take over if it
failed (warm standby). Alternatively, the "spares" could be kept turned off and
only switched on when needed (cold standby). Another common form of hardware
redundancy is disk mirroring.
Replacement Disk: A disk available for use to replace a failed member disk in a
RAID array.
SCSI: (Small Computer System Interface) A processor-independent standard for
system-level interfacing between a computer and intelligent devices, including
hard disks, flexible disks, CD-ROM, printers, and scanners. SCSI can connect up
to eight devices to a single adapter (or host adapter) on the computer’s bus. SCSI
transfers eight bits in parallel in Narrow, or 16 bits in Wide.
SCSI Channel: HP NetRAID Series adapters and integrated HP NetRAID
controllers control the disk drives via SCSI-2 buses called "channels" over which
the system transfers data in Fast/Wide, Ultra/Wide, or Ultra2 SCSI mode. The
HP NetRAID-3Si adapter has three channels, and the HP NetRAID-1Si adapter
has one channel. In HP NetServer LH 3/3r and LH 4/4r, the integrated
HP NetRAID controller can have either one or two channels. In other
HP NetServers, the integrated HP NetRAID controller has two channels.
SCSI Disk Status: A SCSI disk module (physical drive) can be in one of these six
states:
•
Ready: A powered-on and operational disk that has not been configured.
•
Online: A powered-on and operational disk.
•
Hot Spare: A powered-on, stand-by disk ready for use if a disk fails.
•
Failed: Errors on the disk have caused it to fail, or you have used an
HP NetRAID utility to take the drive offline.
•
Rebuild: A disk to which one or more critical logical drives is restoring
data.