Per history, this had been there for several months, seems nagiosgraph’s rrd data updated sometime, and it seems this related to upgrade.
I never paid too much attention on this as nobody else, except me, watching those performance data graphs. However, today I do need to solve this as it’s always bothering that you cannot get data whenever you do need it.
Long story short – and stupid me, obvious a while back whenever I applied my patch to nagios.cfg, I didn’t comment out the first process_performance_data=0, and obviously second process_performance_data=1 didn’t overwrite the first one. Also, even with process_performance_data=0 which disable performance data processing, nagios still processes performance data every time it got restarted, and this cause all mysterious problems.
I do believe nagios behaves wrong in this case – it’s a common sense that configuration can be overwritten by later one with same key, and if configuration tells you don’t do something, DON’T do it even in edge cases, otherwise people will get confused and made debugging really difficult.