Current Varnish status?

Dag-Erling Smørgrav des at
Tue Feb 13 13:51:43 CET 2007

Denis Brækhus <denis at> writes:
> Dag-Erling Smørgrav <des at> wrote:
> > The differences between the released version and the svn trunk are
> > currently very small (a few bug fixes).
> So SVN would actually be more stable then?

Possibly, if your environment triggers the bugs that have been fixed
since the last release.

> > Whether Varnish is usable in a production environment depends on the
> > nature of your application.  Varnish currently does not respect Vary:
> > headers and interacts poorly with cookies, but if you don't use
> > either, you'll be fine.
> Is it possible to define "interacts poorly with cookies"? I do think
> our application relies quite heavily on cookies for session
> handling. Does interacting poorly imply that any site where cookies
> are used do not work well with Varnish, or simply that Varnish does
> not handle caching well when cookies are involved?

Basically, if a page uses cookies, you can't cache it.  That goes for
any proxy, not just Varnish.

By default, Varnish goes into PASS mode if the client includes a
cookie in the request.  It will however cache a page delivered from
the backend even if it contains a cookie, so everybody gets the same
cookie until the page expires...  In Varnish 1.0, this is a feature,
as it was not intended for sites that use cookies.  I expect that in
Varnish 2.0 - perhaps even in 1.1 if we decide to do a 1.1 - it will
be reclassified as a bug, and fixed.

Workaround: if only part of your site uses cookies, you can configure
Varnish to always use PASS mode for that part, and cache the rest.

BTW, I've looked at and did not find any cookies on any
page I visited.

Dag-Erling Smørgrav
Senior Software Developer
Linpro AS -

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