I'd like to see how many requests varnish is sending to each backend via round-robin director. i haven't found out how so far. thanks for any idea
You can't get this numbers from varnish directly, but if youre using round-robin director I'd guess the traffic to each backend will be nearly the 1/n of total ammount where n is number of backends. This is true only if backends all healthy and not skipped from round.
You can still get theese stattistics from backend access log or server-status page or similar, depending on http daemon used.