On Tue, 1 Apr 2008, Beolach wrote:
On Sat, Mar 29, 2008 at 12:20 PM, Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx> wrote:
<snip>
Thanks for sharing your benchmarking methods. I've been running
similar benchmarks, trying to pick the best chunksize for my hardware,
and I also found your previous thread "Fastest Chunk Size w/XFS For MD
Software RAID = 1024k" in the archives. In my benchmarks[1], I see
256k & 128k giving the best results. So now I'm wondering if that's
just because I have different harddrives (Seagate ST31000340NS 1000GB
32MB cache), or if the number of drives is also important - I only
have 4 drives right now, but I plan on getting more when I can afford
to. If I had more drives, would the larger chunksizes (512k or 1024k)
be more likely to perform better than 256k?
Also, would you be willing to share your script for averaging 3
bonnie++ runs? I'm too lazy to write my own, so I've just been doing
single runs.
I do not have a single script to do it actually, it works like this:
# Run bonnie 3 times (script).
for i in 1 2 3
do
/usr/bin/time /usr/sbin/bonnie++ -d /x/test -s 16384 -m p34 -n 16:100000:16:64 > $HOME/test"$i".txt 2>&1
done
# then get the results
$ cat test* | grep ,
p34,16G,80170,99,261521,43,109222,14,82516,99,527121,39,864.3,1,16:100000:16/6411428,83,+++++,+++,6603,30,7780,56,+++++,+++,8959,45
p34,16G,79428,99,266452,44,111190,14,82087,99,535667,39,884.3,1,16:100000:16/643388,26,+++++,+++,7185,34,6364,46,+++++,+++,4040,22
p34,16G,78346,99,255350,42,111591,14,82153,99,527210,38,850.4,1,16:100000:16/642916,21,+++++,+++,18495,81,5614,41,+++++,+++,15727,83
$ cat test* | grep , > results
$ avgbonnie results
p34,16G,79314.7,99,261108,43,110668,14,82252,99,529999,38.6667,866.333,1,16:100000:16/64,5910.67,43.3333,0,0,10761,48.3333,6586,47.6667,0,0,9575.33,50
Nothing special for the average, just a long awk statement hardcoded for 3
runs:
grep ',' "$1" | awk -F',' '{print $1, $2, c += $3/3, d += $4/3, e += $5/3, f += $6/3, g += $7/3, h += $8/3, i += $9/3, j += $10/3, k += $11/3, l += $12/3, m += $13/3, n += $14/3, $15, p += $16/3, q += $17/3, r += $18/3, s += $19/3, t += $20/3, u += $21/3, v += $22/3, w += $23/3, x += $24/3, y += $25/3, z += $26/3, aa += $27/3}' | tail -n 1 | sed 's/\ /,/g'
$ grep ',' results | awk -F',' '{print $1, $2, c += $3/3, d += $4/3, e += $5/3, f += $6/3, g += $7/3, h += $8/3, i += $9/3, j += $10/3, k += $11/3, l += $12/3, m += $13/3, n += $14/3, $15, p += $16/3, q += $17/3, r += $18/3, s += $19/3, t += $20/3, u += $21/3, v += $22/3, w += $23/3, x += $24/3, y += $25/3, z += $26/3, aa += $27/3}' | tail -n 1 | sed 's/\ /,/g'
p34,16G,79314.7,99,261108,43,110668,14,82252,99,529999,38.6667,866.333,1,16:100000:16/64,5910.67,43.3333,0,0,10761,48.3333,6586,47.6667,0,0,9575.33,50
Hope this helps..
[1] My bonnie++ results:
<http://www.xmission.com/~beolach/bonnie++_4disk-ls.html>
Intriguing results you have there, nice sequential read speed.
What FS are you using?
Any special options?
What read-ahead are you using?
What is your stripe_cache_size?
These heavily affect performance.
Justin.
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