A Few Questions About RAID (No, Not the Bug Spray)

[PacoL250]

RAID!? *We fall over, dead.*

Anyway, I just want to know, what is it? I've heard things like Mode 0, 1, etc. How does an EIDE drive plug into a RAID Mobo? For example, I have an IBM 60 GB HDD that I want to work with the ABit KT7A-RAID Mobo.

You can see my confusion.

Thanks!

[Darren Wilson]

Via a standard ATA100 cable like it does to a normal IDE socket. You need at least 2 identical drives to make a RAID configuration.

[Antimatter]

RAID 0: Striping. Turns two drives into one doubling the capacity. Can double the data rate for large files if they're physically stored on different drives.
RAID 1: Mirroring: Looks like one drive to the user(only using half the available capacity). Automatically backs up data from one drive to the other. V. Good for businesses.

[thecoolbean]

um... they kinda have it right. RAID is a Redundant Array of Inexpensive Disks. There are hardware and software solutions. You do NOT need identical hard drives to set up a raid array... just identical partitions (If you set up to different sized drives... your array will be limited by the smaller drive.)

Raid is good for fault tolerance and for speed increase or both depending on what you set up. Raid 0, Raid 1, Raid 0+1 and Raid 5 are the configurations mostly in use today.

Raid 0 - (2 drives) disk striping... data written to the drives is wriiten on alternating clusters so the load is spread evenly. This gives you an array roughly DOUBLE the size of your to drives (10+10=20)

Raid 1 - (2 drives) Disk Mirroring. All data written is written to 2 drives at same time. Because it uses 2 drives your storage space is halved (10)+(10)=10

Raid 0+1 (4 drives) Disk Striping +Mirroring.
In this setup you have 2 Striped arrays mirroring each other. Provides some degree of redundancy but is VERY expensive... 4 hard drives?? ((10+10)+(10+10)) = 20

Raid 5 (3 drives) This usually takes a SCSI solution or Software Raid (Linux, Win2k server) You get increased capacity, redundancy, and performance this way. This gives you the effective capacity of 2 of the drives and one drives does hashing. With raid 5 if ANY of the drives crashes... your array stays up and if you have Hot Swappable bays installed and a controller that handles it.. you can replace a drive on the fly. The best performance and most economical setup. (10+10+10)=20

The best detailed explanation i have run across is at RedHat's site: http://www.redhat.com/support/manual...e/ch-raid.html

For a home system I would stay away from raid 0 (no backup if one fails) and consider RAID1 if you want basic redundancy. If you are considering RAID 0+1 that may be an option... as going the preferred routes takes a $400+ SCSI Raid5 controller and 3 SCSI Drives. Good Luck.