[Gluster-users] Slow performance from simple tar -x && rm -r benchmark

[Bryan Whitehead]

I have a number of labs I test my glusterfs installs on. From
Infinband 40G w/switch and also some cheap $800 boxes on a gig
network.

None of them exhibit the poor performance i'm seeing in your post - so
I'm just throwing out the differences I'm seeing with your config vs
mine.

Another option you might want to try is increasing the max number of threads:

gluster volume set <name> performance.io-thread-count 64


On Mon, Mar 19, 2012 at 2:34 AM, Chris Webb <chris at arachsys.com> wrote:
> Bryan Whitehead <driver at megahappy.net> writes:
>
>> I didn't see any sync's after the tar/rm commands...
>
> By default, ext4 flushes both metadata and data every five seconds, so a
> post-benchmark sync tends to make little difference on a reasonable large test,
> but for completeness:
>
>  # time bash -c 'tar xfz ~/linux-3.3-rc7.tgz; sync; rm -rf linux-3.3-rc7; sync'
>  real    0m23.826s
>  user    0m20.681s
>  sys     0m2.392s
>
> vs
>
>  # time bash -c 'tar xfz ~/linux-3.3-rc7.tgz; sync; rm -rf linux-3.3-rc7; sync'
>
>  real    4m24.067s
>  user    0m24.692s
>  sys     0m7.588s
>
> showing very similar timings and the same effect.
>
>> try using xfs instead of ext4.
>
> I'll build the xfs tooling, add kernel support, and give this a go, but I'm
> surprised you think changing the underlying filesystem would eliminate the big
> gap between native and gluster performance. I could imagine it improving both
> somewhat, but if anything, I'd expect a higher performance filesystem to
> amplify the differences. Do you think that glusterfs does something that's
> particularly expensive on ext4, much more expensive than the operations proxied
> through it?
>
> Best wishes,
>
> Chris.