Hardware RAID Technology -
Redundant Array of Independent Disks:
RAID can be achieved in one of 2 ways,
either through hardware or software. Hardware being the better solution.
Why would anyone want to use RAID? Since RAID is a disk subsystem that
increases performance and/or provides fault tolerance Disk
Systems, anyone seeking either would benefit. Especially Digital Video
or Digital Audio Editors requiring Workstations with capacity & speed
of performance for Streaming large amounts of Digital Data.
Developed initially for servers and
stand-alone disk storage systems, RAID is increasingly becoming available
in Desktop PCs as mentioned above. RAID was previously known as Redundant
Arrays of "Inexpensive" Disks. RAID can consist of either
ATA/ATAPI or SCSI HD's. RAID installations are typically either RAID 0, 1
or RAID 5. Read your Specs and know your needs before getting involved
with RAID. Yes, RAID is getting easier and less expensive. And now with WDC
250 GB HD's, are you sure you still need RAID? An absolute maybe!?!
Adaptec sees RAID as a Business Protection
Requirement. Intel has further enhanced RAID with
Intel Matrix Storage Technology using the ICH6R Controller Hub which
combines the benefits of RAID 0 performance and RAID 1 protection on two
Hard Disk Drives through the Four Port SATA RAID Controller. Intel also
allows O/S Migration for a future RAID Upgrade if implemented @ time of
System Build using a hidden partition on the Boot Drive Partition.
Faster Boot Times can also be achieved using RAID.
Since RAID resides in two varieties, we're further Specifying those details
below. The nomenclature:
- Hardware RAID
= Bios Configured RAID Controller. Could be SCSI,
Parallel ATA or Serial
- Software RAID
= Software (O/S or Software Application) Control.
Below, we have included the definitions
of RAID Technologies.
RAID LEVEL 0
Level 0 is disk striping only, which interleaves data across
multiple disks for better performance. It does not provide
safeguards against failure.
RAID LEVEL 1
Uses disk mirroring, which provides 100% duplication of
data. Offers highest reliability, but doubles storage cost.
RAID LEVEL 2
Bits (rather than bytes or groups of bytes) are interleaved across
multiple disks. The Connection Machine used this technique, but this is a
RAID LEVEL 3
Data is striped across three or more drives. Used to achieve the
highest data transfer, because all drives operate in parallel. Parity bits
are stored on separate, dedicated drives.
RAID LEVEL 4
Similar to Level 3, but manages disks independently rather than in
unison. Not often used.
RAID LEVEL 5
Most widely-used. Data is striped across three or more drives for
performance, and parity bits are used for fault tolerance. The parity bits
from two drives are stored on a third drive.
RAID LEVEL 6
Highest reliability, but not widely used. Similar to RAID 5, but does two
different parity computations or the same computation on overlapping
subsets of the data.
RAID LEVEL 10
Actually RAID 1,0. A combination of RAID 1 and 0 (mirroring and
JBOD - Non-RAID
(Just a Bunch Of Disks) A group of hard disks
in a computer that are not set up as any type of RAID configuration. No
are just a bunch of disks which might be addressed as one larger HD
(spanning) or individually (as an additional ATA Controller) - Note: Depends upon
the Vendors use of this definition. Verify before you buy!
SPAN – Concatenated Stripe
- A linking of disparate HDs to be seen as 1. [See
www.promise.com - Desktop
Controllers, FastTrak TX Controller card.]
technet.microsoft.com - Planning Disk Configuration
"To determine disk configuration, consider importance relative of
capacity, cost, reliability, and performance in your environment."
Explained - RAID Recovery Online
RAID Levels Quoted from www.computerlanguage.com
- Buy the Dictionary & tell them you heard about it @ BuildOrBuy
and from www.Microsoft.com!