Justin Piszcz wrote:
> Btw, max sectors did improve my performance a little bit but
> stripe_cache+read_ahead were the main optimizations that made everything
> go faster by about ~1.5x. I have individual bonnie++ benchmarks of
> [only] the max_sector_kb tests as well, it improved the times from
> 8min/bonnie run -> 7min 11 seconds or so, see below and then after that is
> what you requested.
>
> # echo 3 > /proc/sys/vm/drop_caches
> # dd if=/dev/md3 of=/dev/null bs=1M count=10240
> 10240+0 records in
> 10240+0 records out
> 10737418240 bytes (11 GB) copied, 399.352 seconds, 26.9 MB/s
> # for i in sde sdg sdi sdk; do echo 192 >
> /sys/block/"$i"/queue/max_sectors_kb; echo "Set
> /sys/block/"$i"/queue/max_sectors_kb to 192kb"; done
> Set /sys/block/sde/queue/max_sectors_kb to 192kb
> Set /sys/block/sdg/queue/max_sectors_kb to 192kb
> Set /sys/block/sdi/queue/max_sectors_kb to 192kb
> Set /sys/block/sdk/queue/max_sectors_kb to 192kb
> # echo 3 > /proc/sys/vm/drop_caches
> # dd if=/dev/md3 of=/dev/null bs=1M count=10240
> 10240+0 records in
> 10240+0 records out
> 10737418240 bytes (11 GB) copied, 398.069 seconds, 27.0 MB/s
>
> Awful performance with your numbers/drop_caches settings.. !
Can you repeat with /dev/sda only?
With fresh reboot to shell, then:
$ cat /sys/block/sda/queue/max_sectors_kb
$ echo 3 > /proc/sys/vm/drop_caches
$ dd if=/dev/sda of=/dev/null bs=1M count=10240
$ echo 192 > /sys/block/sda/queue/max_sectors_kb
$ echo 3 > /proc/sys/vm/drop_caches
$ dd if=/dev/sda of=/dev/null bs=1M count=10240
$ echo 128 > /sys/block/sda/queue/max_sectors_kb
$ echo 3 > /proc/sys/vm/drop_caches
$ dd if=/dev/sda of=/dev/null bs=1M count=10240
> What were your tests designed to show?
A problem with the block-io.
Thanks!
--
Al
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