Le 07/05/2014 09:45, Kim Holmebakken a écrit :
Hey,
Im currently working on a bachelor thesis where I need to measure iops
on my storage solution.
I have set up a "frontend" server(ubuntu server 13.10) which has zfs
on linux running, and is connected to an iSCSI RAID(SAN).
When I use this command:
fio --directory=/pool --size=128M --direct=0 --fallocate=none
--rw=randrw --refill_buffers --norandommap --randrepeat=0
--ioengine=sync --bs=4k --rwmixread=100 --iodepth=16 --numjobs=16
--runtime=60 --group_reporting --name=4krandreadtest
[...]
These values are extremly high and I suspect that these are the RAM
speed being returned to me.
Is there anyway to get a more realistic result?
You do cached IOs (as direct=0), only 128M of data and everything into a
file. As a result, yes everything is getting into the host's cache.
If you want to determine the ISCSI performance byitself, I suggest not
using file but the block device and do direct IOs (direct=1).
If you want to keep your filesystem you have two options : enabling the
direct=1 and/or making IOs at twice the size of your host memory.
Hope this helps,
Erwan
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