Frank van Bortel wrote:
> Frank van Bortel wrote:
>
>>Had not seen this whilst replying to the other.
>>
>>Of course I was talking about hardware RAID.
>>
>>And as right as you probably are, I have never seen
>>hardware mirroring being substantially slower than
>>single disks for writing. Note substantially is not
>>the same as measurable; it can be measured, sure.
>>
>
> Any comparism between Single disk and SATA RAID
> controllers (I know - not SCSI, but SCSI will
> and should outperform SATA) shows:
>
> 1) Access times on RAID1 are better than single disk
> (http://tweakers.net/reviews/536/17)
>
> 2) Most h/w RAID controllers show better write throughput
> on RAID1 than on single disks; those that show decreased
> performance do *not* show 33% decrease, but far less (15%)
> (http://tweakers.net/reviews/536/19)
>
> 3) In an average database environment, mixed IO, RAID1
> outperforms single disks (http://tweakers.net/reviews/536/25)
>
> 4) You want RAID5 with more than 3 disks - OT
SATA and SCSI drives are built with the exact same physical
components. I'd be surprised if there is much difference in
performance.
--
Daniel A. Morgan
http://www.psoug.org
damorgan_at_x.washington.edu
(replace x with u to respond)
Received on Mon Jun 13 2005 - 13:27:16 CDT
