Installation guide

G-4 AcceleRAID 170 Installation Guide
Offline: A Logical Drive is in an “offline” state if...
No data can be read from it or written to it.
System commands issued to offline logical drives are returned with an error
status: no operations can be performed on offline logical drives. A logical
drive can be “offline” under one of two situations described below:
• It is configured with a redundant RAID level (1, 3, 5, or 0+1), and two
or more of its SCSI drives are not “online”; or
• It is configured at RAID level 0, JBOD, or in a spanned set, and one or
more of its SCSI drives are not “online.”
Logical Drives
See “System Drives.”
Mirroring
Refers to the 100 percent 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.”
RAID
RAID stands for Redundant Array of Independent Disks. The Mylex RAID
controllers implement this technology to connect up to 15 SCSI devices per
channel. Several different forms of RAID implementation have been
defined. Each form is usually referred to as a “RAID level.” All the RAID
levels supported by Mylex RAID controllers are shown below.