[Gluster-users] Performance loss from 3.4.2 to 3.6.2

[Nico Schottelius]

Hello,

re-tested, however also changed some more parameters than just the
volume option due to reinstall:

    Ubuntu 14.04 -> CentOS 7 (*)
    Glusterfs 3.6.2 from RPM glusterfs-epel.repo vs. gluster-3.6 ppa

Otherwise the test setup is the same. The results are:

    3.6.2-CentOS7-cluster.ensure-durability-on:     ~65-72 MiB/s
    3.6.2-CentOS7-cluster.ensure-durability-off:    ~86-89 MiB/s

So the question from our side is now, what is exactly the threat that
we have when using cluster.ensure-durability-off?

Also I wonder which other tuning parameters you can recommend for
a workload in which we _only_ have VM images (i.e. big files)?

Cheers,

Nico

(*) Using CentOS 7, as we are interested in using libgfapi with qemu.

Nico Schottelius [Thu, Feb 12, 2015 at 12:07:33AM +0100]:
> Hello,
> 
> switching from 3.4.2 to 3.6.2 reduces our average test performance dramatically.
> 
> Our test setup: directly connected 1 GBit/s hosts setup with:
> 
>     rm -rf /home/gluster/.glusterfs/
>     rm /home/gluster/*
>     setfattr -x trusted.glusterfs.volume-id  /home/gluster/
>     setfattr -x trusted.gfid /home/gluster/
>     gluster volume create xfs-plain replica 2 transport tcp vmhost1-cluster1:/home/gluster vmhost2-cluster1:/home/gluster
>     gluster volume start xfs-plain
> 
> Afterwards we run our near real world test
> 
>     mount -t glusterfs vmhost1-cluster1:/xfs-plain /mnt/gluster/
>     while true; do dd if=redmine-from-ceph-20150204 of=/mnt/gluster/testvm bs=1M; rm /mnt/gluster/testvm; done
> 
> The results are
> 
>     3.4.2: ~71-72 MiB/s     [ubuntu 14.04]
>     3.6.2: ~59-64 MiB/s     [gluster-3.6 ppa]
> 
> We have removed 3.6.2 and re-installed 3.4.2 and can consistently reproduce
> these numbers over hours of testing.
> 
> Is there any configuration change that we need to incorporate to run
> 3.6.2 faster or is this a known problem?
> 
> Cheers,
> 
> Nico
> 
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