SCSI RAID - how does it work?

Bames_Jond

Distinguished
Aug 20, 2001
93
0
18,630
Can anyone please tell me what the difference between RAID0, RAID1 and RAID5 is? How does the different systems work, how fast are they compared to each other and what about data security. Which RAID system is the fastest, the most stabil and/or the most secure??? If you got a link to where I can read about them and maybe also the different SCSI standards I would be very happy.

My name is Jond, Bames Jond.

My ACPI incompatible network adapter killed my SB Live!
 
G

Guest

Guest
Raid 0 = Stripe set. atleast 2 drives, no fault tolerance, fastest raid.

Raid 1 = Mirroring. 2 drives that duplicate one another, you only pull info from one specific drive, the other is a copy. This is slower than a single drive.

Raid 2 = Duplexing. same thing as mirroring accept with one controller per drive. This is faster than mirroring but same as a single non raid drive.

Raid 5 = Stripe set w/ parity. Atleast 3 drives(one for parity), one drive can fail and still recover your data. This method is faster than Raid 1 or 2, but raid 0 is the ultimate speed demon.

Ultra2 = 80MB/s
Ultra3 = 160 MB/s
these are the max interface transfer rates. Good SCSI drives put out around 50 MB/s average. Ideal performance would be 3-4 drives in a raid 0. If you want fault tolerance/performance go with Raid 5.

Disclaimer:) The best method depends on what you need it for, and how many drives you will use.

For more info go checkout www.adaptec.com, they have some good products and info sheets.