Varnish Performance Issue

Paras Fadte plfgoa at
Wed Dec 3 11:30:29 CET 2008

Hi Poul,

The traffic is steady and the server is not directly externally
available , It acts as a caching server behind a load balancer for the
origin servers. I have attached bandwidth graph for our perusal. What
confuses is the sudden Spike in CPU usage .

Thank you.


On Wed, Dec 3, 2008 at 3:43 PM, Poul-Henning Kamp <phk at> wrote:
> In message <75cf5800812022248n6704cef5k44ea4ba44876a31c at>, "Paras
>  Fadte" writes:
>>I am faced with following performace issue with respect to Varnish.
>>Load on Varnish increases suddenly at times. When this happens ,
>>"varnishhist" shows a high number of misses and the cache hit ratio
>>decreases and the response time  increases.
> I think this sounds pretty normal, try examining the traffic pattern
> and see if coincides with the arrival of robots/spiders at your
> site.
> If you want to, you can return a temporary error in vcl_miss if the
> user-agent indicates a robot or spider, that way they don't pull
> your entire site content into the cache.
> Poul-Henning
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
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