varnish fetching, stroring and serving cached 404 from backend server
david.birdsong at gmail.com
Wed Aug 18 09:50:08 CEST 2010
On Tue, Aug 17, 2010 at 7:59 PM, Michael Loftis <mloftis at wgops.com> wrote:
> Varnish caching, or not caching, is completely controlled by the VCL. Not
> having yours noone can help you. However, the *default* VCL makes anything
> with a Cookie or HTTP Authentication header from the client uncacheable.
Fair enough, I should have known vcl would be helpful, *but I didn't
think that statement was entirely true.
"completely controlled by the VCL"...I thought there were boundaries
that varnish operated in and no amount of vcl magic would override
it...such as beresp.cacheable, if that boolean evaluated to false, I
thought that varnish will never cache. Is that incorrect?
Anyway, here's the vcl:
> --On Tuesday, August 17, 2010 1:13 PM -0700 David Birdsong
> <david.birdsong at gmail.com> wrote:
>> I've been struggling to understand why and how varnish is deciding to
>> cache a 404 response from a backend. It's very tough to reproduce.
>> I've thrown millions of test URLs at varnish where my testing
>> application will respond back randomly with a 404 and I can't trigger
>> it. Only user traffic is able to trigger this weird behavior.
>> Anybody have any experience with this?
>> Here's a varnishlog of a 404.
>> I'm working to capture the varnishlog of the resource actually getting
>> fetched and stored.
>> varnish-misc mailing list
>> varnish-misc at varnish-cache.org
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