[Gllug] Production system - Linux 2.4.24, LVM and cciss

[Martin A. Brooks]

At 23:14 11/01/2004 +0200, you wrote:
>I disagree - in fact, I haven't found a single comparison where RAID5's
>overall performance is claimed to be better than RAID1+0 (I've been

One of us is misunderstanding.

RAID 0, 1 and 5 all do different things.   On a "total storage space" 
orientated setup, I can _always_ give you a RAID5 setup that will 
outperform any combination of raid levels 0 and 1 in terms of raw i/o 
speed. By definition a RAID1 scenario must write twice as much data and 
give no performance gain when reading.

Nearly the biggest factor for RAID5 is the number of spindles. RAID5 works 
more slowly with fewer bigger disks. In any situation where you think it's 
slower, simply half the size of the disks and double the number of disks 
you have.


Martin A. Brooks, Clues Ltd.
http://www.clues.ltd.uk/

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