Varnish constantly restarting

[Alexander Staubo]

On Mon, Jul 5, 2010 at 9:08 AM, Per Buer <perbu at varnish-software.com> wrote:
> There is only one place where SIGQUIT is used and that is where you're
> hitting it. I'd try to disable the whole check by setting the
> cli_timeout ridiculously high. If you have proper monitoring the risk
> isn't high.

That makes sense. I was slow in catching onto the fact that Varnish
was simply killing its child because it was slow in responding to the
pings; from my point of view it looked more like Varnish was hanging.

> You might be having issues  with your io scheduler (cfq
> can be a real disaster) or a bigger working set then your memory can
> handle (swap on Linux doesn't work very well).

How do I go about determining the underlying cause? As far as I can
see, it's not caused by any increase in traffic.

I am tracking every varnishstat metric using Munin, and not seeing
anything out of the ordinary at the instances when Varnish kills
itself -- nor with any of the other system metrics tracked with Munin.
There should be plenty of memory available, and I'm not seeing any
swapping.

Linux 2.6.24 + CFQ reports weird CPU usage [1] that screws up our
graphs, but that's hardly an indication of anything. However, we
should probably try to switch away from CFQ.

[1] http://grab.by/grabs/af573a30e5be0774edcfffc77294f4d8.png