Varnish 3.0.x - Gunzip / Gzip

Lee Trout lee at
Thu Feb 9 05:23:41 CET 2012

I seem to remember Poul-Henning showing a diagram at VUG4 that showed
varnish both compressing and uncompressing as it processed content and
there are notes about that here

I would think that turning gzip support off would lead to seeing no gunzip
operations but based on the documentation it sounds like it only affects
how the objects are stored in the cache. It goes on to mention that if a
client does not send an accept encoding Varnish will unzip the content.
Perhaps because you have turned this off you are seeing gunzips when a
client isn't accepting gzip or whenever there is a cache miss Varnish is
gunzipping before it puts the content in the cache.

"Enable gzip support. When enabled Varnish will compress uncompressed
objects before they are stored in the cache." from

Unless you are seeing some specific performance degradation I would leave
it turned on (assuming the documentation is correct and turning it on
merely enforces storing compressed content).

Maybe someone else will chime in and tell me I've got it all wrong :)


On Wed, Feb 8, 2012 at 3:34 PM, Lane, Richard <rlane at> wrote:

> I have tried setting “http_gzip_support” to off/false via startup
> parameter but I still see that Gunzip operations are still occurring in
> Varnish when looking at Varnishstat output. I would like to turn this off
> because I have Apache behind Varnish that is already handling Gzip/Deflate
> operations. Anyone know how to turn it off?
> /etc/sysconf/varnish:
>     .....
>              -p shm_reclen=1024\
>              -p http_gzip_support=false \
>              -u varnish -g varnish
>    ......
> Varnishstat Output:
>     .....
>            1          .            .   vmods - Loaded VMODs
>           98         0.00         0.77 n_gunzip - Gunzip operations
>            1         0.00         0.01 LCK.sms.creat - Created locks
>    ......
> Cheers,
> Richard
> _______________________________________________
> varnish-misc mailing list
> varnish-misc at
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