[Gluster-users] Performance for KVM images (qcow)

[Bryan Whitehead]

I just want to say that trying to run a VM on almost any glusterfs
mounted fuse is going to suck when using 1G nic cards.

That said your setup looks fine except you need to change "replica 4"
to "replica 2". I'm assuming you want redundancy and speed.
Replicating to all 4 bricks is probably not what you wanted. By
setting replica to 2 you'll be able to lose any 1 of the 4 bricks and
still run without data missing.

gluster volume create replica 2 <... list all 4 bricks>



On Tue, Apr 9, 2013 at 3:49 AM, Stephan von Krawczynski
<skraw at ithnet.com> wrote:
> On Tue, 09 Apr 2013 03:13:10 -0700
> Robert Hajime Lanning <lanning at lanning.cc> wrote:
>
>> On 04/09/13 01:17, Eyal Marantenboim wrote:
>> > Hi Bryan,
>> >
>> > We have 1G nics on all our servers.
>> > Do you think that changing our design to distribute-replicate will
>> > improve the performance?
>> >
>> > Anything in the gluster performance settings that you think I should change?
>>
>> With GlusterFS, almost all the processing is in the client side.  This
>> includes replication.  So, when you have "replica 4", the client will be
>> duplicating all transactions 4 times, synchronously.  Your 1G ethernet
>> just became 256M.
>
> Let me drop in that no clear mind does it this way. Obviously one would give
> the client more physical network cards, best choice as many as there are
> replications, and do the subnetting accordingly.
>
> --
> Regards,
> Stephan
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