>> What sort of tools are you using to get these benchmarks, and can I >> used them for ext3? The only simple tools that I found that gives semi-reasonable numbers avoiding most of the many pitfalls of storage speed testing (almost all storage benchmarks I see are largely meaningless) are recent versions of GNU 'dd' when used with the 'fdatsync' and 'direct' flags and Bonnie 1.4 with the options '-u -y -o_direct', both used with a moderately large volume of data (dependent on the size of the host adapter cache if any). In particular one must be very careful when using older versions of 'dd' or Bonnie, or using bonnie++, iozone (unless with -U or -I), ... [ ... ] > for i in 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 32768 65536 > do > cd / > umount /r1 > mdadm -S /dev/md3 > mdadm --create --assume-clean --verbose /dev/md3 --level=5 --raid-devices=10 --chunk=$i --run /dev/sd[c-l]1 > /etc/init.d/oraid.sh # to optimize my raid stuff > mkfs.xfs -f /dev/md3 > mount /dev/md3 /r1 -o logbufs=8,logbsize=262144 > /usr/bin/time -f %E -o ~/$i=chunk.txt bash -c 'dd if=/dev/zero of=/r1/bigfile bs=1M count=10240; sync' > done I would not consider the results from this as particularly meaningful (that 'sync' only helps a little bit) even for large sequential write testing. One would have also to document the elevator used and the flushed daemon parameters. Let's say that storage benchmarking is a lot more difficult and subtle than it looks like to the untrained eye. It is just so much easier to use Bonnie 1.4 (with the flags mentioned above) as a first (and often last) approximation (but always remember to mention which elevator was in use). - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
