Unused backend somebackend, defined:
Is solved with
-p vcc_err_unref=off
In CentOS / RHEL you can add that to
/etc/sysconfig/varnish
You’d also have to pass that option if you’re testing your vcl config
varnishd -p vcc_err_unref=off -C -f /etc/varnish/default.vcl
Using varnishadm you can reload your vcl after editing it, without restarting varnish.
That means your cache is intact:
# varnishadm varnish> vcl.load default /usr/local/varnish/etc/varnish/default.vcl 200 VCL compiled. varnish> vcl.use default 200 varnish>
What I found really practical was that this way I also could detect and fix errors in my vcl config, without varnish going down.
varnish> vcl.load default /usr/local/varnish/etc/varnish/default.vcl
106
Message from VCC-compiler:
Expected ')' got '{'
(program line 73), at
('input' Line 105 Pos 51)
if ( !( req.url ~ "(login_form|manage)") {
--------------------------------------------------#
Running VCC-compiler failed, exit 1
VCL compilation failed