What is varnish? (Was: Please test varnish-2.1.0-2 for F-13)

Ingvar Hagelund ingvar at redpill-linpro.com
Mon Apr 19 09:43:55 UTC 2010

I was asked to give a short description of what varnish is. 

Varnish is a state of the art, high performance http accellerator. Think
squid in reverse caching mode, but powered by the dark side of the
force, on steroids*.

Varnish is Free Software, available under the BSD license.

Some highlights
- A modern design, using advanced features in Linux 2.6, FreeBSD 6/7 
  and OpenSolaris
- A very flexible compiled configuration language
- Load balancing with health checking of backends
- Partial support for ESI
- URL rewriting
- Graceful handling of "dead" backends
- Live statistics and logging

Varnish is used to accellerate well-known sites like Slashdot, Wikia and
Twitter, to name a few.

More info at http://www.varnish-cache.org/

Please consider testing varnish-2.1.0-2.fc13 for F-13, see below.


*) Real life cases has shown one varnish instance out-performing a
cluster of 12 squid boxes.

* Ingvar Hagelund:
> I think it's important that varnish-2.1.0-2.fc13 is included in F-13,
> and hope that it's not too late.
> It was submitted by bodhi today, and can also be downloaded from koji.
> Please test the update and give feedback through bodhi.
> Snipped from the bodhi update request:
> Details
>         Upgrade to new upstream release 2.1.0. This upgrade is important
>         because
>               * The previous 2.0 series will be discontinued within the
>                 lifetime of F-13
>               * 2.1.0 contains a fix for CVE-2009-2936. It is not
>                 probably that upstream will backport this fix for the
>                 2.0 series
>         These changes should be important enough to include
>         varnish-2.1.x in F-13, even after the freeze.
> Ingvar

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