APC SCSI-SATA II manual Wb Ro Ds, Gs Dc Gc Dg S.M.A.R.T

RAID width, RAID copy, RAID row (RAID cell in one row)

WT

RAID width, copy and row are used to describe one VG. E.g.:

1.One 4-disk RAID 0 volume: RAID width= 4; RAID copy=1; RAID row=1.

2.One 3-way mirroring volume: RAID width=1; RAID copy=3; RAID row=1.

3.One RAID 10 volume over 3 4-disk RAID 1 volume: RAID width=1; RAID copy=4; RAID row=3.

Write-Through cache write policy. A caching technique in which the completion of a write request is not signaled until data is safely stored on non-volatile media. Each data is synchronized in both data cache and the accessed physical disks.

WB

RO

DS

Write-Back cache write policy. A caching technique in which the completion of a write request is signaled as soon as the data is in cache and actual writing to non-volatile media occurs at a later time. It speeds up system write performance but needs to bear the risk where data may be inconsistent between data cache and the physical disks in one short time interval.

Set the volume to be Read-Only.

Dedicated Spare disks. The spare disks are only used by one specific VG. Others could not use these dedicated spare disks for any rebuilding purpose.

GS

DC

GC

DG

S.M.A.R.T.

Global Spare disks. GS is shared for rebuilding purpose. If some VGs need to use the global spare disks for rebuilding, they could get the spare disks out from the common spare disks pool for such requirement.

Dedicated Cache.

Global Cache.

DeGraded mode. Not all of the array’s member disks are functioning, but the array is able to respond to application read and write requests to its virtual disks.

Self-Monitoring Analysis and Reporting Technology.

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