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Posted by Colin McFadyen on 02/28/07 05:06
In <bmk9u21551lnspmek5a8uqlbpekjn9j6su@4ax.com> MassiveProng <MassiveProng@thebarattheendoftheuniverse.org> writes:
>On Tue, 27 Feb 2007 19:39:36 -0000, Doug Jacobs
><djacobs@shell.rawbw.com> Gave us:
>>
>>How exactly does one "stripe" a bit anyways? Mirrored - sure. Parity -
>>sure. Striped? What's smaller than a bit?
> You're an idiot.
> Nine drives.
> Take a Byte
> Place one bit in each drive, and the parity bit on the parity drive.
> No mirroring, dumbass.
> The throughput is at maximum.
> You can lose up to two drives, and rebuild their contents on the
>replacement drive without missing a beat. There are even hot swap
>versions about.
Nope. You could only lose 1 drive.
> So once the file has been written, your data integrity is at
>maximum. Absolutely no way to lose a file. You'd have to trash at
>least three drives in the bit region to kill the files.
Wrong.
Wasn't that called RAID2? The member of the RAID family that never
really caught on due to high cost and a rather complex setup.
Actually, the optimum setup was to use 14 drives. 10 data disks and
4 ECC disks. However, since most modern disks have ECC on board, it
made RAID2 redundant pretty quickly. Using modern ECC drives with
other RAID levels provides superior access and fault tolerence.
RAID3 would probably do fine for video applications. It uses byte level
striping with dedicated parity and offers excellent sequential reads
and writes.
If you have more cash to spend, RAID 0+1/10 offers excellent fault
tolerence, availability, random and sequential reads and writes.
Bottom line is that RAID2 never really made it to primetime and is not
used in any modern system.
http://www.storagereview.com/guide2000/ref/hdd/perf/raid/index.html
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