Varnish Cache comes with a set of parameters that affects behaviour and performance. Most of these parameters can be set on the Varnish command line (through varnishadm) using the param.set keyword.

Some parameters can, for security purposes be read only using the ‘-r’ command line switch to varnishd.

We don’t recommend that you tweak parameters unless you’re sure of what you’re doing. We’ve worked hard to make the defaults sane and Varnish should be able to handle most workloads with the default settings.

For a complete listing of all the parameters and a short descriptions type in the CLI. To inspect a certain parameter and get a somewhat longer description on what it does and what the default is type and the name of the parameter, like this:

varnish> shortlived
shortlived                  10.000000 [s]
                            Default is 10.0
                            Objects created with TTL shorter than this are
                            always put in transient storage.