On Tuesday 31 May 2011, Michael Monnerie wrote:
# ./flashbench --open-au --open-au-nr=5 --erasesize=$[8 * 1024 * 1024] /dev/sdd --random 8MiB 21.3M/s 4MiB 17M/s 2MiB 11.1M/s 1MiB 7.7M/s 512KiB 5.67M/s 256KiB 6.19M/s 128KiB 5.13M/s 64KiB 5.69M/s 32KiB 3.19M/s 16KiB 2.2M/s
Can you guide me with what I should test next?
Try larger values for --open-au-nr=X. You are on the right track, the erasesize is obviously 8 MB, and the number of open AUs is most likely more than 6.
For both linear and --random, you can pass --open-au-nr=32 just for fun, to see what happens (the performance should be horrible, no need to let it run to the end in that case), then start with smaller values (8, 12, 16, 20) to see where the cutoff is. Find the largest fast one and the smallest slow one for linear and random modes.
With the --open-au tests, just use --blocksize=512 as a start. The number only defines when the test stops.
Arnd