I tried to search but did not succeed. My question, if I change my rrd4j config what will happen with the history? I’m thinking of keeping the minute values for a month instead of a week, but if this deletes the history I would not be happy. Or is this not an issue and will it be intact (of course needing some time - in my case a month - to adapt to the new setting)?
Changing the config of a rrd4j database is a bit tricky. IMHO a changed config will NOT be used directly from a running service. You would need to stop the service, delete or move the old .rrd files and restart the service.
If you think about writing your history data in a .rrd file created with the new archive setting, you would have to set all each and every datapoint in each and every archive manually. Personally, I would hesitate to do such.