I have been using it for years as well but instead of having it running all the time I just run "vnstat -i eth0 -tr" every minute with cron and log that 5 second average result
Is there a reason why? I find vnstat to use zero noticeable resources even under high traffic load (1Gb)
Same.. It is one of the first things I install on a new server. I have never noticed it using gobs of RAM or CPU.
I'd hope it does, considering the man page says it literally reads the kernel's interface counters from /proc (or in other words, the kernel does all the counting). The daemon has its own polling time as well.
I have scripts collect all sorts of other data about the server and send it to central log server every minute, i do not really need exact data more of a snapshot (traffic, ram, cpu, harddrive etc etc) and well I do not like running things all time on server, tho' yes vnstat is very light