I've been hacking a little bit on jrobin, implementing missing RPN/VDEF
operators in jrobin that exist in rrdtool.
You can checkout the current state of things at:
One thing that has been bugging me is when comparing the xport outputs
there are some off by one/two errors.
The first one I found is that given a specific start time, jrobin is
consistently 1 period earlier than rrdtool (and hence 1 period longer).
rrdtool also goes beyond the end time. If you had a step size of 5
seconds, specified an end time of '2012-12-12 12:12', the last time
period it would export out is 2012-12-12 12:12:05".
Any feedback would be appreciated.