Re: SW RAID read performance

["Owen Heisler" <owenh000@gmail.com>]

On 8/3/06, Dave Ewart <davee@sungate.co.uk> wrote:
> On Thursday, 03.08.2006 at 07:30 -0400, Justin Piszcz wrote:
> > From my benchmarking on my RAID1 (dual raptor RAID1) it appears it
> > reads from one drive or the other.
>
> It all depends on which disk controllers you're using and their
> throughput.
>
> I have two, separate SATA disks on two different SATA controllers and
> read performance in a RAID-1 configuration *is* (nearly) twice that of a
> single disk, in many situations.  I think I've got the benchmark
> statistics somewhere...
>
> If "it appears it reads from one drive or the other" is the case, then
> you probably have a bottleneck somewhere else.  Are these disks on the
> same controller channel?

I have an Abit AX8
(http://www.abit-usa.com/products/mb/products.php?categories=1&model=215),
with four SATA ports (two controllers).

I have for some time been planning a RAID5 setup using 3 SATA drives
on this motherboard.  There would be two SATA drives on one
controller, and one SATA drive on the second controller.  I had
assumed that a loss of performance with multiple drives (on a single
controller) only applied to PATA; does it apply to SATA too?  If so, I
won't get any better performance with RAID5...

Thanks for your help.