Varnish 3.x Expiry Thread overload

Ricardo Bartolome Mendez ricardo at tuenti.com
Mon Aug 26 16:27:34 CEST 2013


Hi Lasse,

There are no bans in use. I think we can manage to stop sending small
objects to a subset of servers and see how it behaves, even unfortunately
we'll need to wait few weeks until we check if it helps or not. We'll also
give a try to -smalloc to see how it behaves.

Shall I understand that you are actively looking into the issue because a
customer of yours is being affected or shall I open a ticket in Varnish
Trac? Is it a known issue? Is there already an existing ticket? I'm willing
to help, so don't hesitate to ask me any kind of information that can help
you to spot the issue.

Regards,


2013/8/26 Lasse Karstensen <lkarsten at varnish-software.com>

> On Mon, Aug 26, 2013 at 11:10:10AM +0200, Ricardo Bartolome Mendez wrote:
> [..]
> > Does anybody have an idea about what's going on?
>
> Hi Ricardo.
>
> I ran this by Martin and Dag.
>
> Just to make sure, are there a lot of bans in use? We're assuming no.
>
> Our best guess based on the data supplied is that the tiny object handling
> in
> the file backend is the source of this. Many small objects mixed with
> larger objects makes a bad combination on -sfile.
>
> We've seen a problem that did appear similar on a customer rig not long
> ago.
>
> Our best suggestion is to reconfigure the system for swap and use -smalloc
> instead, and see how that goes. This is contrary to the usual
> recommendations.
>
> If you can I'd recommend adding some disk IO latency monitoring.
>
> --
> With regards,
> Lasse Karstensen
> Varnish Software AS
>



-- 
Ricardo Bartolomé Méndez
Systems Engineer
+34.672.194.729
tuenti.com
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