Varnish burns the CPU and eat the RAM

[Martin Boer]

Hello Romain,

Wat does happen when you limit the amount of memory/space used ? Say 
something like

-s file,/mnt/varnish/varnish_storage.bin,7G


Regards,
Martin

On 03/02/2011 05:46 PM, Romain LE DISEZ wrote:
> Hello all,
>
> I'm pretty new to Varnish. I'm deploying it because one of our customer
> is going to have a special event and the website is pretty slow (I'm
> working for an Internet hosting company). We are expecting more than
> 1000 requests per seconds.
>
>  From what I read here and there, this should not be a problem for
> Varnish.
>
> My problem is that when Varnish is using cache ("deliver", as opposed to
> "pass"), the CPU consumption increases drasticaly, also the RAM.
>
> The server is a Xeon QuadCore 2.5Ghz, 8GB of RAM.
>
>
> With a simple test like this (robots.txt = 300 bytes) :
>      ab -r -n 1000000 -c 1000 http://www.customer1.com/robots.txt
>
> CPU consumption is fluctuating between 120% and 160%.
>
> Second point is that Varnish consumes all the memory. Trying to limit
> that, I made a tmpfs mountpoint of 3G :
>      mount -t tmpfs -o size=3g tmpfs /mnt/varnish/
>
> But varnish continues to consume all the memory
>
> My configuration is attached to this mail. Varnish is launched like
> this :
> /usr/sbin/varnishd -P /var/run/varnish.pid
>      -a :80
>      -f /etc/varnish/default.vcl
>      -T 127.0.0.1:6082
>      -t 120
>      -w 120,120,120
>      -u varnish -g varnish
>      -S /etc/varnish/secret
>      -s file,/mnt/varnish/varnish_storage.bin,100%
>      -p thread_pools 4
>
> I also tried to launch it with parameter "-h classic"
>
> It is installed on a Centos 5 up to date, with lastest RPMs provided by
> the varnish repository.
>
> If I put a return (pass) in vcl_fetch, everything is fine (except the
> backend server, of course). It makes me think, with my little knowledges
> of Varnish, that the problem is in the delivering from cache.
>
> Output of "varnishstat -1", when running ab, is attached.
>
> Thanks for your help.
>
>
>
>
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