X-varnish and Via question

Martin Boer martin.boer at netclever.nl
Mon Aug 2 16:02:52 CEST 2010


Hi all,

In our setup we have 2 varnishes next in parallel.
If one of them gets a question which it cannot serve it will 'ask' the 
other first. If the other also doesn't have the object the question goes 
through to the backend servers.
This works fine with as side effect is that we get a 'Via 1.1 varnish, 
1.1 varnish' response header and 2 entries in the X-varnish response as 
well.
So far so good. But when I tested the HA parts of our site and 
stop/started both varnishes a couple of times the headers have been 
increasing rapidly to
'Via 1.1 varnish, 1.1 varnish, 1.1 varnish, 1.1 varnish...'
This is because when the restarted varnish asks its brother the answer 
already contains 2 'varnishes'. When restarting the other varnish it 
will ask the other one for the object and the headers increase again.

I can probably 'unset' and 'set' the response headers but is there a 
better way ?
Regards,
Martin




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