:In short — only by stopping and starting a VE. In some cases you need to keep VE in a stopped state for a few minutes.

:Consider what happens if you will reset you sent/received packets/bytes statistics on the network interface — programs which reads will be screwed up.

:So the proper thing to watch for is not the current value of, say, failcnt, but whether it is increased (from the previous reading) or not. You can write a simple shell script to do just that.