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Neil
Asked: 2013-10-24 17:14:17 +0800 CST

How do you get Varnish to serve cached objects with an expired TTL when the backend returns 503?

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I'm trying to get Varnish to serve up cached objects with an expired TTL when requesting a new copy of the object from the backend returns a 503 error.

There is a Varnish Grace feature which will do this when the backend is unhealthy, but it doesn't work when the backend is passing its health check.

cache

1 Answers

  1. That's where saint mode comes in - you can use it to mark the backend's response as unusable, and start the request over again, either using a different backend or stale content from grace mode.

    if (beresp.status == 503) {
  set beresp.saintmode = 10s;
  return(restart);
}
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