Persistence Errors

openhabian3 on RPi4:

I am getting these errors for two of my items:

2021-06-09 12:19:00.836 [ERROR] [d4j.internal.RRD4jPersistenceService] - Could not create rrd4j database file '/var/lib/openhab/persistence/rrd4j/Motion_Kitchen.rrd': Read failed, file /var/lib/openhab/persistence/rrd4j/Motion_Kitchen.rrd not mapped for I/O

I saw another post which said that it comes from using persistence for switches which is supposed to only be for numerical values:

It sounds like I can delete those files & fix this but I am using the default persistence configuration. I am assuming this happened because I chose these items to appear in a graph? My memory is that the graph DID show the switches state properly. Anyway, am I right that this was teh cause of these errors?

Is there a different configuration to use if you want persistence for switches?

What’s the status of your file system? You can see this error when the disk is out of space.

Ultimately this isn’t a Switch or persistence error per-se, this error indicates a failure to open the DB file for writing. So this is a file system error. The file system may be out of space, or it may be read only, or something like that. Maybe that file has the wrong file permissions for some reason.

There is no different config for Switches. Either they are supported in which case they are saved, or they are no in which case there is no attempt to save them.

Yes I saw something storage space as well so I installed the System Info binding & it says I have 62% space available.

I’m only getting this error for one of the two dehu switches on this system, and one of four motion sensors which is interesting. I didn’t do any fiddling with file settings so I don’t know why permissions for just those files would have changed.

One other thing, are these Items changing really fast? I saw similar problems with a Group configured to save on update. The updates came too fast and rrd4j couldn’t keep up.

Nothing like that. Especially the dehu switch. Just sitting there waiting for a command. Is it possible that we had a graph with those two items in it through a reboot or something? So those files were open & got corrupted?

Anything is possible but I would expect a different error if the file were merely corrupted. This error indicates that openHAB is not able to even open the file.