ArrayMasStor K Series
ÒInstallation Instructions and Procedures.Ó
Copyright
Ó
Advanced Technology and Systems Co., Ltd., 11/2001 Rev. A
11
Trademarks and Trade names that may appear within this document are the property of their respective owners.
RAID Overview
Redundant Array of Inexpensive Disks (RAID) is a storage technology used to improve the
performance, and increase the reliability, of a data storage system. This technology was developed
around the idea of grouping multiple disk drives together (an array) to provide features and
functionality thatÕs not available in a single disk drive.
Two primary concepts underlying RAID are:
a)
That distributing data over multiple disk drives can dramatically improve performance
and
b)
That using multiple drives properly allows for any one drive to fail without loss of data and
without system downtime. In the event of a disk failure, disk access will continue normally and
the failure will be transparent to the host system.
Though originally conceived with SCSI drives in mind, RAID principles have been very
successfully applied to IDE, Fibre Channel, and other types of drives. The K-Series RAID system
employs IDE drives.
NOTE:
The K-Series RAID system has been designed to tolerate a single fault in any major
component except the controller itself. One of any (or even one of ÒeachÓ in a worst case
scenario) redundant component can fail and the data on the system will still be maintained
and available. These redundant components include the drives, fans, and power supplies
within the system.
Non-RAID Storage
One common option for expanding the capacity of standard (non-RAID) disk storage is to simply
install multiple disk drives into the system and then combine (or concatenate) them end to end.
This approach to expanding capacity is generally referred to as
disk spanning
.
(Note that the
K-Series RAID system
does not support non-RAID storage.)
With disk spanning, the total disk capacity is equivalent to the sum of the capacities of all drives in
the combination. The combination is then presented to (and appears as) a single logical drive to the
system. Thus, for example, combining four 100 GB drives in this way would create a single
ÒlogicalÓ or ÒvirtualÓ drive with a total disk capacity of 400 GB.
Disk spanning is generally considered non-RAID due to the fact that it provides neither
redundancy nor improved performance. Disk spanning is inexpensive, flexible, and easy to
implement; however, it does not improve the performance of the drive-group and any single disk
failure will result in total data loss.
