[Gluster-users] GlusterFS as virtual machine storage

[Pavel Szalbot]

On Sun, Sep 10, 2017 at 3:02 PM, Vijay Bellur <vbellur at redhat.com> wrote:
>
>
> On Fri, Sep 8, 2017 at 5:56 AM, Pavel Szalbot <pavel.szalbot at gmail.com>
> wrote:
>>
>> This is the qemu log of instance:
>>
>> [2017-09-08 09:31:48.381077] C
>> [rpc-clnt-ping.c:160:rpc_clnt_ping_timer_expired]
>> 0-gv_openstack_1-client-1: server 10.0.1.202:49152 has not responded
>> in the last 1 seconds, disconnecting.
>>
>
>
> 1 second is not an ideal value for ping timeout. Can you please set it to 30
> seconds or so and simulate the problem? I would be interested in observing
> your logs with a higher ping timeout value.

I restored the default 42 seconds and do not experience crashes now
even with gfapi except occasional performance drops reported by fio.
This applies to both replica 3 with and without arbiter. I had
previously used timeout 3 or 5 seconds and 1sec was set at the end of
the last week so I tested the 5 seconds timeout now and got crash
quite fast.
I guess the ping to the nodes that are actually up must timeout as
well and that's the reason for IO errors. But 5 seconds seem like
quite a long time. Or could it be something else?

BTW I restart primary mount point (the one specified in
mount.glusterfs) IO stops for several seconds and then fluctuates
between 0 and something more or less expected and this fluctuation is
present until the node comes up. If I restart the other node in the
cluster, this does not happen. Is this to be expected?

Thanks
-ps