On Fri Dec 21, 2012, Thomas Fjellstrom wrote:
> I'm setting up a new nas box (7x2TB on a IBM M1015 8 port sas card flashed
> to 9211IT mode) and was thinking about adding an SSD cache to it. I've
> been following bcache's development, but it seems to have stalled a bit.
>
> I've got a 240G Samsung 470/810 that I'd like to use for this.
>
> Also I was wondering if anyone has any tips on the best (or their
> preferred) way to set up a "big" raid6 array with a single filesystem. I'm
> probably going to stick with XFS, but I'm not married to it, if there's
> something better for a big media (audio, video, disk images, backups, etc)
> volume I'd love to hear about it.
So my array has finally finished resyncing, and I've run a simple iozone test
on it formated with xfs, and I'm seeing some somewhat low write results:
moose@mrbig:/mnt/mrbig/data/test$ iozone -a -s 32G -r 8M
random random
bkwd record stride
KB reclen write rewrite read reread read write
read rewrite read fwrite frewrite fread freread
33554432 8192 212507 210382 630327 630852 372807 161710
388319 4922757 617347 210642 217122 717279 716150
Is this normal for a 7 disk (2TB seagate barracudas) raid array on a pcie x8
sas controller?
I was thinking it might be alignment issues, but there are no partitions on
the disks, and xfs seems to have correctly set up the sunit and swidth
settings (128/640 for a 7 disk raid6). While 200MB/s is probably more than I
need day to day, I'd like to make sure it is set up properly.
--
Thomas Fjellstrom
thomas@xxxxxxxxxxxxx
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