Anand, My VCL extract coped with a backend failure - if all backends fail on their monitoring probe (which, for example, might monitor any database replication lag etc), then Varnish will fail over to sending requests to any backend, regardless of its perceived health. This allows for the possibility of service continuing in a worst case scenario, whilst still behaving well when there's just a partial degradation of backends.
Rob On 23 Dec 2010, at 08:05, Traian Bratucu wrote: > Anand, > > You may want to look at grace mode, it could resolve your issue. When the > backend is too busy you can serve stale content for a minute or something. > > Have a look: > http://www.varnish-cache.org/docs/trunk/tutorial/handling_misbehaving_servers.html > > Traian > ________________________________________ > From: [email protected] > [[email protected]] On Behalf Of Anand Shah > [[email protected]] > Sent: Thursday, December 23, 2010 6:26 AM > To: Robert Shilston > Cc: [email protected] > Subject: Re: Too many 503 backend errors > > Thanks robert, > > But i have already tried all this stuff's. The problem with probing is that > if your back-end is unhealthy for a second and if varnish declares it > unhealthy due to some reason than it shows backend unhealthy for next 5 mins > or so whereas the interval is only 5s. So if i m running on one back-end all > the requests for this backend fails. > > The one i m using is a very domain with 3000 req/s. > > so cannot afford a second of unhealthy network or unreachability. > > Regards, > Anand > > > _______________________________________________ > varnish-misc mailing list > [email protected] > http://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc _______________________________________________ varnish-misc mailing list [email protected] http://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
