When logged into the Varnish server, you can see which requests are most common using the commands below. These will help determine popular content and also assist with troubleshooting during high-load times.
The following command shows the requests from the Internet to Varnish:
varnishtop -i TxURL
The following command shows the requests from Varnish to the backend server (web server):
varnishtop -i RxURL