Yesterday I ran into this issue, that my dummy switch which is linked to a channel creates some log files which are showing that there are some problems with the persistence, see:
00:57:27.087 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'JobaDevSwitch' changed from OFF to ON
00:57:27.091 [ERROR] [rd4j.internal.RRD4jPersistenceService] - Could not create rrd4j database file '/var/lib/openhab/persistence/rrd4j/JobaDevSwitch.rrd': /var/lib/openhab/persistence/rrd4j/JobaDevSwitch.rrd (Permission denied)
Thanks in advance for some advice, how to solve this? Moreover thanks for some additional advice to get to the root of this issue.
My advice is to provide more information. We do not know how you installed OH or what troubleshooting steps you have already tried. It appears to either be a permissions or disk space issue which would be OS related, outside of OH.
I used the default Ubuntu-way by apt, see openHAB on Linux | openHAB
The system is running on Ubuntu 20.04. Ubuntu runs in a virtual machine on a windows host. Of course I can set the permissions properly on my system, but I guess this will be an issue which got its origin somewhere else.
I observed the same behaviour, when using a .things file - the files which should be generated in /var/lib/openhab/jsondb have the user and group root instead of openhab. I guess it is the right time to create a ticket on github. I will go for it.