Parameters

These are run-time parameters of the Varnish Cache daemon. Most of them can be changed on the fly, but some might not take effect for some time (e.g: Changing default_ttl will only apply to new content). Others might require a child restart.

Best practices is to keep your parameters as close to the defaults as possible.

View non-default parameters

Running

You can stop and start the Varnish child. This clears out all statistics and the cache itself.

While stopped, Varnish does not listen for HTTP connections, but does accept administrative commands (e.g: setting parameters, VCL, and starting it back up again).

For information about panics, see /help/panic. The links below just use this API.

Cache invalidation

The agent only supports banning. For other methods, use VCL.

The agent issues ban commands over the Varnish CLI. It will not free up memory unless you use smart bans.

Keep in mind that if your cache is empty, your ban list will also always be empty. In other words: If you are just testing this and banning something, then get an empty ban list instead of seeing your own ban: make sure the cache has content.

List bans

Varnishtop

This is a JavaScript implementation of varnishtop. It can help you determine what traffic you should look closer at (e.g: cache misses), what web servers you are using (e.g: Server headers), etc.