Too many 503 backend errors

Traian Bratucu traian.bratucu at
Thu Dec 23 09:05:56 CET 2010


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:

From: varnish-misc-bounces at [varnish-misc-bounces at] On Behalf Of Anand Shah [imanandshah at]
Sent: Thursday, December 23, 2010 6:26 AM
To: Robert Shilston
Cc: varnish-misc at
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.


More information about the varnish-misc mailing list