D-Link ShareCenter Pro DNS-1550-04 User Manual page 42

ShareCenter Pro User Manual
Disk Array Problems:
Disk array Problems typically result from a physical drive failure. The most
common Problem is a degraded disk array. The RAID controller can rebuild a
degraded disk array.
A more serious, but far less common Problem is an Incomplete Array. An
incomplete array results from a physical drive that fails or becomes missing
during:
−
RAID level migration
−
Disk array transport
Disk Array Degraded:
Disk arrays are made up of physical drives. Logical drives are created on the
disk array. When one of the physical drives in a disk array fails:
−
The operational status of disk array becomes Degraded.
−
The operational status of logical drives becomes Critical.
−
The operational status of physical drive becomes Dead or
Offline.
Disk Array Offline:
Disk arrays are made up of physical drives. Logical drives are created on the
disk array. When a disk array and its logical drives go Offline, the data stored
in the logical drives is no longer accessible.
−
Logical drives based on fault-tolerant disk arrays — RAID 1, 5,
6 and 10,— go Offline when two physical drives are removed
or fail.
−
Logical drives based on non-fault tolerant disk arrays — RAID
0 — go Offline when a one physical drive is removed or fails.
42