On Thursday 28 July 2011, Ajax Criterion wrote:
--> aligned to 4MB blocks. FAT 32 in the front, EXT4 in the back again (I'll likely destroy this again with the --findfat test, but what the hell... FS in the back will get changed around a lot while I benchmark multiple filesystems).
The --open-au test also destroys the data, you just might be able to run a little bit longer. There is generally no reason to even create a partition table in order to run flashbench, just boot from a different drive than the one you want to test.
bash-4.1# flashbench -O --open-au-nr=10 /dev/sdc --erasesize=$[4*1024*1024] --blocksize=4096 4MiB 11.8M/s 2MiB 13.2M/s 1MiB 13.6M/s 512KiB 13.6M/s 256KiB 13.5M/s 128KiB 11.2M/s 64KiB 15.2M/s ^C ^C bash-4.1# flashbench -O --open-au-nr=13 /dev/sdc --erasesize=$[4*1024*1024] --blocksize=4096 4MiB 6.54M/s 2MiB 5.55M/s 1MiB 5.95M/s 512KiB 3.15M/s 256KiB 2.51M/s 128KiB 894K/s 64KiB 467K/s ^C bash-4.1# flashbench -O --open-au-nr=12 /dev/sdc --erasesize=$[4*1024*1024] --blocksize=4096 4MiB 6.07M/s 2MiB 5.83M/s 1MiB 5.9M/s 512KiB 5.95M/s 256KiB 5.45M/s 128KiB 4.91M/s 64KiB 4.82M/s 32KiB 4.44M/s 16KiB 2.86M/s 8KiB 772K/s ^C bash-4.1#
---> There seems to be a clear breakdown after 12 AU's ...
Yes, that is pretty clear from your numbers.
why am I bouncing around between 5-6 and 11-13 M/s??
I'm not sure, but what I can imagine is happening is that the drive can switch each erase block between linear optimized more (13 MB/s) and random access mode (6 MB/s). When you do something that has a random pattern, including going beyond 12 erase blocks, it will go into the random mode, in order to cope at all. After writing linearly a few times, the controller decides to get back into linear optimized mode. This is a very smart thing to do for the controller.
bash-4.1# flashbench -O --open-au-nr=12 /dev/sdc --erasesize=$[4*1024*1024] --blocksize=4096 --random 4MiB 11.2M/s 2MiB 8.51M/s 1MiB 5.8M/s 512KiB 3.6M/s 256KiB 5M/s 128KiB 3.86M/s 64KiB 3.12M/s 32KiB 3.23M/s 16KiB 1.89M/s ^C bash-4.1# flashbench -O --open-au-nr=13 /dev/sdc --erasesize=$[4*1024*1024] --blocksize=4096 --random 4MiB 8.89M/s 2MiB 7.31M/s 1MiB 5.55M/s 512KiB 3.7M/s 256KiB 4.99M/s 128KiB 3.74M/s 64KiB 3.11M/s 32KiB 3.25M/s ^C bash-4.1# flashbench -O --open-au-nr=15 /dev/sdc --erasesize=$[4*1024*1024] --blocksize=4096 --random 4MiB 9.85M/s 2MiB 7.47M/s 1MiB 4.7M/s 512KiB 2.54M/s 256KiB 995K/s ^C bash-4.1# flashbench -O --open-au-nr=14 /dev/sdc --erasesize=$[4*1024*1024] --blocksize=4096 --random 4MiB 7.13M/s 2MiB 5.82M/s 1MiB 4.01M/s 512KiB 3.67M/s 256KiB 4.94M/s 128KiB 3.23M/s 64KiB 3.43M/s 32KiB 3.37M/s 16KiB 1.79M/s ^C
--looks to be 14 open AU's for random.
Yes.
bash-4.1# mkdir /mnt/sdc1 bash-4.1# mount /dev/sdc1 /mnt/sdc1 bash-4.1# umount /dev/sdc1
---> mounts fine.
Just lucky that you didn't overwrite any actual data. flashbench does not write into the first 16 MB on the --open-au test in order to avoid the FAT optimized blocks, so if all your important data is there, you won't notice the damage.
bash-4.1# flashbench --findfat --fat-nr=8 --erasesize=$[4*1024*1024] --random --blocksize=512 /dev/sdc 4MiB 4.96M/s 13.4M/s 13.3M/s 13.4M/s 13.3M/s 13.4M/s 13.3M/s 13.3M/s 2MiB 5.16M/s 9.27M/s 9.28M/s 9.22M/s 9.19M/s 9.39M/s 9.16M/s 9.43M/s 1MiB 5.24M/s 5.86M/s 5.86M/s 5.84M/s 5.85M/s 5.9M/s 5.87M/s 5.92M/s 512KiB 5.29M/s 3.77M/s 3.77M/s 3.77M/s 3.77M/s 3.77M/s 3.77M/s 3.77M/s 256KiB 2.92M/s 5.5M/s 5.49M/s 5.51M/s 5.48M/s 5.49M/s 5.5M/s 5.46M/s 128KiB 4.54M/s 4.61M/s 4.61M/s 4.61M/s 4.6M/s 4.62M/s 4.6M/s 4.61M/s 64KiB 4.16M/s 3.58M/s 3.6M/s 3.6M/s 3.6M/s 3.59M/s 3.59M/s 3.6M/s 32KiB 5.61M/s 4.17M/s 4.17M/s 4.18M/s 4.19M/s 4.19M/s 4.18M/s 4.18M/s 16KiB 4.1M/s 2.83M/s 2.83M/s 2.83M/s 2.82M/s 2.82M/s 2.83M/s 2.82M/s 8KiB 1.35M/s 1.33M/s 1.33M/s 1.33M/s 1.33M/s 1.33M/s 1.33M/s 1.33M/s 4KiB 743K/s 839K/s 837K/s 838K/s 838K/s 838K/s 838K/s 838K/s ^C
I think there is nothing to see here.
For some reason, when I run a scatter plot, I get a very long straight line...I'm trying to sort that out to get a better read, to verify the 4MB eraseblock...
It's quite possible that that's all you can get out of this drive.
Arnd