This is all very vague...
I ran vnstat, it tells me to create the database, I did, now I am back at the state where i have a running vnstatd but vnstat tells me "not enough data".
I have not changed anything to /etc/vnstat.conf. Update Interval is 30 sec. But even after 30 sec the database-files don't seem to get touched. They still have their old timestamp.
I will wait a little longer, but I expect that even tomorrow I will simply get "not enough data":...
This is evidently utter crap software.
Can someone point me to an alternative?