Trouble understanding why Varnish retries on backend timeouts

Tollef Fog Heen tfheen at
Mon Nov 12 11:01:57 CET 2012

]] .

> I recently got bit by this functionality, and I was hoping that someone
> could shed some light on why this is the default behavior for varnish.

Because there's a race between when we submit a GET on a connection and
when the backend closes it on us because of a timeout.

> From everything I have read online,
> the retry should only occur once, but I could have sworn I saw it
> happen multiple times.

If you restart in vcl_error, it can happen multiple times.

> and even a patch (which doesn't seem to have been applied):

We should probably apply this.  Martin, do you want to resubmit it
(possibly after cleaning it up)?

Tollef Fog Heen
Technical lead | Varnish Software AS
t: +47 21 98 92 64
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