About Disk Array; Disk Array Interpretation; Disk Array Member; Disk Array Types Supported By Promise Pdc20378 - SOLTEK SL-B8D-F Manual

SL-B8D-F/SL-B8D-FR

5-0 About Disk Array

5-0-1 Disk Array Interpretation

A "Disk Array" is formed from a group of 2 or more disk drives with the
RAID (Redundent Array of Independent Disks) technology. The aim of
a Disk Array is to provide better perfornance and/or data fault tolerance.

5-0-2 Disk Array Member

The individual disk drive in an array is called a "member". Each member
of a specific disk array is coded in their "reserved sector" with
configuration information that identifies the drive as a member. All disk
members in a formed disk array are recognized as a single physical
drive to the system.

5-0-3 Disk Array Types Supported by Promise PDC20378

PDC20378 on this mainboard supports three types of Disk Arrays: RAID
0, RAID 1.
1. RAID 0 (or Striping mode):
RAID 0 is a group of 2 to 4 Disk Drives configured together with
RAID technology to provide better data transfer performance than a
single drive since the workload is balanced between the array
members. Reads and Writes of RAID 0 data are interleaved between
multiple drives. When any disk member fails, it affects the entire array.
The disk array size is equal to the number of drive members times
the smallest member capacity. For example, one 1GB and three 1.
2GB drives will form a 4GB (4x1GB) disk array.
2. RAID 1 (or Mirroring mode):
RAID 1 is a group of 2 Disk Drives configured together with RAID
Technology to provide the fault tolerance function. Writes duplicate
data on to RAID 1 while reads are performed in parallel. If one of the
mirrored drives suffers a mechanical failure (e.g. spindle failure) or
does not respond , the remaining drive will continue to function. This
is called Fault Tolerance.
The drive capacity of RAID 1 is half the total drive capacity of two
equal-size drive.
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