Dave Ewart píše v Čt 03. 08. 2006 v 19:31 +0100:
On Thursday, 03.08.2006 at 07:30 -0400, Justin Piszcz wrote:
I have 2 disks in RAID 1 and I expected reading will be approx. 2x
faster then a single disk reading because there can be used the same
technique as on RAID 0. I tested it with bonnie++. Can linux SW RAID
1 read "in stripes" to boost the reading performance?
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?
Dave.
My benchmarks have shown me ~45MB/s both on single drive and SW RAID 1
(so no speed up at all). I have UDMA133 PATA (it can theoretically
sustain speed over 100MB/s) controller so I would expect the SW RAID 1
will bring me at least more then 50MB/s when reading, right?
David
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