Justin Piszcz wrote:
On Wed, 11 Jun 2008, Justin Piszcz wrote:
On Wed, 11 Jun 2008, Bill Davidsen wrote:
Justin Piszcz wrote:
First, the original benchmarks with 6-SATA drives with fixed
formatting, using
right justification and the same decimal point precision throughout:
http://home.comcast.net/~jpiszcz/20080607/raid-benchmarks-decimal-fix-and-right-justified/disks.html
Now for for veliciraptors! Ever wonder what kind of speed is
possible with
3 disk, 4,5,6,7,8,9,10-disk RAID5s? I ran a loop to find out, each
run is
executed three times and the average is taken of all three runs per
each RAID5 disk set.
In short? The 965 no longer does justice with faster drives, a new
chipset
and motherboard are needed. After reading or writing to 4-5
veliciraptors
it saturates the bus/965 chipset.
This is very interesting, but a 16GB chunk size bears no
relationship to anything I would run in the real world, and I
suspect most people are in the same category.
I based my bonnie++ test on:
http://everything2.org/?node_id=1479435
So I could compare to his results.
I use a 1024k (1MiB) with 16384 stripe, this offered the best overall
read/write/rewrite performance AFAIK.
1024k chunk size (raid5 chunk size)
echo 16384 > stripe_cache_size
Please don't explain any more, I'm confused enough already. I can't make
those numbers match 16G no matter how I add them, either the contents of
the column labeled "size:chunk size" isn't the size of the chunk, or you
have a multiplier floating around that I don't see. And you eliminated
the degraded performance, since your stripe_cache_size is less than
(raid5 chunk size)*(#disks), I would expect the reads in degraded mode
to be dog slow because the don't fit in cache, even if 1024k is what I
call chunk size and certainly not if chunk size is 16G.
--
Bill Davidsen <davidsen@xxxxxxx>
"Woe unto the statesman who makes war without a reason that will still
be valid when the war is over..." Otto von Bismark
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