T-shirt
Rated XXX
|
 Posted: Thu, 11 Mar 2004 13:27:57 Post Subject: |
 |
|
| Dr. EvilCheeze wrote: | .........
Here is how RAID 5 works. Let's say you have 5 drives, and one is the parity drive, so you are writing across 4 drives. Let's say it's using even parity. So when you do a write on the drive let's just say it write:
Drive 1: 0
Drive 2: 0
Drive 3: 1
Drive 4: 1
It now has to do the math, 0+0+1+1 = 2 or EVEN so on drive 5 it would write a 0. ........... |
One small edit/clarfication to EC's post
the parity is distributed among the drives as well, which is what makes it 100% after a single drive failure.
Also with a 'smart' caching controller drives it is nearly as fast as ATA100, and allowed true hot swapping of drives, while making more effiencent uses of drive space than RAID1
Remember it was designed for fast (at the time) but expensive SCSI drive arrays. With ATA133 and even Faster S-ata drives at almost throwaway prices and consumer grade/priced controllers that allow hot-swapping and/or hot spares RAID 5 is not really needed in small stand alone servers.
AC&NC has a good explaination of the pros and cons of each raid level |
|
