Installation guide

Glossary
Manual No. 771961 G-7
Logical Drives
A logical drive is equivalent to a “system” drive. Logical drives are presented
to the operating system as available disk drives, each with a capacity
specified by the Mylex Disk Array Controller.
Logical Unit Number (LUN)
A SCSI representation of a system drive (logical drive) on a given channel
and target ID.
Mirroring
Refers to the 100% duplication of data on one disk drive to another disk
drive. Each disk will be the mirror image of the other.
Pack
See “Drive Groups (or Drive Packs)” .
Parity
See “Rotated XOR Redundancy” .
Physical Drive States
Refers to a drive’s current operational status. At any given time, a drive can
be in one of five states: READY, ONLINE, STANDBY, DEAD, or
REBUILD.
The controller stores the state of the attached drives in its non-volatile
memory. This information is retained even after power-off. Hence, if a disk
drive is labeled DEAD in one session, it will stay in the DEAD state until a
change is made either by using a system level utility or after a rebuild. Each
of the states is described below:
Ready: A disk drive is in a “ready” state if it...
Is powered on; and
Is available to be configured during the current session but remains
unconfigured.