rrd4j stops logging after some hours

[WARN ] [.o.c.p.e.PersistenceExtensions] - There is no queryable persistence service registered with the name ‘rrd4j’

I’ve seen another post with this warning and changed the entries for folder scanning in openHAB.log but unfortunately it doesn’t help me.

Still after one or two hours openHAB stops logging into rrd (for all items !) and also stops executing at least some rules, but as it seems not all rules. Eg I have a rule for showing the time/date in the UI that stops, while a rule for motion sensors seems to continue working.

When restarting openHAB (sudo service openhab stop/ … start) it works for an hour or so, but the same behavior afterwards.

This is quite new since some days and I thinks I didn’t change the system that much (some rules, 6 files)

RPi2, Oracle Java, latest raspbian. rrd4j jars still in the correct folders, no changes here.

Any hint is appreciated

Thanks in advance

no ideas? how can I “debug” the execution of rules?
is there something like
<logger name=“org.openhab.persistence.rrd4j” level=“DEBUG” />
for the “rules engine” or for the persistance in the logback.xml?

The reason seemed I had too many items.
Is there a maximum amount for items in OH?


I have a setup (RPI2, Oracle Java, etc) like yours and I am thinking of adding persistence like rrd4j. I appreciate any comments to what to use.

  • How many items do you have?
  • How did you figure out the problems with to many items?
  • Will you try another persistence provider?



in my setup I have now 36 groups and round about 120 items, but approximately half of them are variables for rules, storing some historic data (e.g. max energy used today, yesterday, …) or used for charts.

I did lots of tests and started with one rules file, waited for a couple of hours and when I realized that OH still logs and executes the rules, I added another rules file and so one. Than I added new items and the rules stopped executing. So I reduced the amount of items and tested again. And it seemed that this was the root cause. Now all rules files (8) are active again and logging still works since some days.

Since I do not need the logged values for a longer time (month/years), I will stick to rrd4j.
MySQL needs far too much resources on my RPi2.

Hope that helps…


Thanks for the response!