Troubleshooting Varnish — Varnish version 3.0.4-rc1 documentation
▻https://www.varnish-cache.org/docs/3.0/tutorial/troubleshooting.html
Specifically if you see the “Error in munmap” error on Linux you might want to increase the amount of maps available. Linux is limited to a maximum of 64k maps. Setting vm.max_map_count in sysctl.conf will enable you to increase this limit. You can inspect the number of maps your program is consuming by counting the lines in /proc/$PID/maps