On Mar 3, 2004, at 5:20 PM, Reko Turja wrote:
RAID-1 will be about 50% faster than RAID-5 doing reads regardless of
size, and will also be *much* faster doing small writes-- by a factor
of 4, perhaps.

The abovementioned figures seem more like comparing RAID-0 (striping) to RAID-5 (striping with ECC) than RAID-5 to RAID-1 (mirroring). In my experience mirroring is always the slowest RAID in terms of retrieving data, writes might be quite comparable with RAID-1 and RAID-5 though.

Your mileage may vary. :-)

However, consider that RAID-1 (mirroring) read performance should always be better than RAID-0 (striping) because you can get the data you want using a single read from either device regardless of size, and you can do things like distribute reads geometrically to reduce head motion for the RAID-1 case-- whereas with reads above the stripe size, the RAID-0 case requires you to access both devices and glue the results together.


[EMAIL PROTECTED] mailing list
To unsubscribe, send any mail to "[EMAIL PROTECTED]"

Reply via email to