User Guide

AMD-RAIDXpert2 User Guide
53987 Rev. 3.01 June 2016
26
Arrays, Disks and RAID Levels
Chapter 3
Table 7. Array States
State
Description
Normal
The Normal state is displayed when everything is functioning correctly.
Ready
The Ready state is displayed while an array is being created.
Critical
The Critical state is displayed when the array is no longer redundant (fault
tolerant) because of one or more disk failures. Arrays can still be read and written
to, but the data is no longer protected should another disk fail.
Offline
The Offline state is displayed when arrays cannot be read or written to because of
one or more disk failures.
Whether an array is marked as Critical or Offline depends upon what RAID level it is and how
many disks within the array have failed. Note the changes in state in Table 8.
Table 8. Failure States by RAID Level
RAID Level
This Failure State
Is Displayed Whenever
RAID1
(Redundant Arrays)
Critical
A single disk fails.
Offline
Two or more disks fail.
RAID10
(RAID Levels with Multiple
Redundancies)
Critical
A single disk fails in any one of the
sets.
Offline
All disks in a set fail.
Volume and RAID0
Offline
A single disk fails.
More than one array can be created using the same set of disks. If a disk is disconnected that
belongs to more than one array, only the arrays that try to access the disk and receive I/O errors
report the failure. For example: there are two arrays, both of which are RAID5 sets, and both use
disk 4. If a system that is being used by array 1 receives an I/O error when trying to communicate
with disk 4, the state of array 1 changes to Critical. However, the state of array 2 using disk 4 does
not change to Critical until an I/O error is reported. If systems using array 1 are not
communicating with failed disk 4, the state of array 1 still displays as Normal.
If a rescan of all channels is performed after disconnecting a disk, the state of every array using
the missing disk changes from Normal to either the Critical or Offline, depending on the RAID
level.