check_rrdtraf sometimes returns 0 network traffic

[avandemore]

Clone all the data on to an identical system and time the run there? There is no other way to get an estimate I'm aware of.

You could possibly use a ramdisk to speed things up, but I doubt that's going to help much as the bottleneck almost certainly isn't disk io.

Or you could do something fancy like construct a wrapper for the cron cmd which saves time run info in a file and allows the existing cron to run as normal.