Party Line: varnish 3.x is EOL. Move to Varnish 4 Looks like you're logging the client side in varnishlog. Try to catch one of the Backend transactions that does this. You'll have to use varnishlog without either -c or -b or -m specified, and trawl through it manually.
varnishadm debug.health might help as well. If all backends in a director are unhealthy, varnish will serve an immediate 503 if the request goes to that director. -Jason On Wed, Oct 14, 2015 at 3:54 PM, Vlad Rusu <[email protected]> wrote: > Good day everyone, > > I am trying to get to the bottom of the 503s sporadically logged by our > Varnish servers. During monitoring, it all comes down to monitoring the > state of my backends ++ varnishlog. > > Most of the 503s come with a FetchError “backend write error: 0 (Success)” > — and I can’t seem to find anything on the internet to describe what this > might mean. > > —> FetchError c backend write error: 0 (Success) <— > > Also, none of the relevant counters in varnishstat are showing any > increase (i.e. backend_unhealthy, backend_busy, backend_fail, > fetch_failed..) > > For that same request, looking at ReqEnd, it doesn’t look to me like any > timeout was reached (like connect_timeout, first_byte_timeout, > between_bytes_timeout, > ..) > > —> ReqEnd c 221990096 1444847550.110866785 1444847550.116131306 > 0.000048876 0.000905752 0.004358768 <— > > > *Any chance we could get a list of possible FetchError messages and what > they might mean — at least something to put us on a right track? Would > surely help knowing where to start looking, especially when everything > seems fine.* > > Also, in this FetcError scenario, *is it expected to see retries from > Varnish?* If so, why would Varnish only retry some of the backends in a > director and not all of them (or the .retries value)? > > 44 VCL_return c hash > 44 VCL_call c pass pass > 44 Backend c 20 drpau_ssl_director drpau34ssl > 44 FetchError c backend write error: 0 (Success) > 44 Backend c 51 drpau_ssl_director drpau31ssl > 44 FetchError c backend write error: 0 (Success) > 44 VCL_call c error deliver > 44 VCL_call c deliver deliver > 44 TxProtocol c HTTP/1.1 > 44 TxStatus c 503 > 44 TxResponse c Service Unavailable > > Should these be reflected in varnishstat’s “backend_retry”? > > Thank you guys! > Vlad Rusu > > _______________________________________________ > varnish-misc mailing list > [email protected] > https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc >
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