This may be a zram problem, what is the output of zramctl if it is what I think it is then all you have to do is simply uninstall and reinstall zram as it was a bug in the code that has since been fixed.
Hmm, it may be the problem I’m thinking of. Go ahead and try uninstalling zram and reinstalling. You can use sudo openhabian-config menu option 38 to do so. As a secondary debug step, what does your RAM usage look like?
i had just 1 sonoff POW that made troubles and tried Option 38 and now all my files have this ERROR
before i had
2021-08-20 00:55:52.668 [ERROR] [d4j.internal.RRD4jPersistenceService] - Could not create rrd4j database file '/var/lib/openhab/persistence/rrd4j/Sonoff_POW_1_ReactivePower.rrd': Invalid file header. File [/var/lib/openhab/persistence/rrd4j/Sonoff_POW_1_ReactivePower.rrd] is not a RRD4J RRD file
now i have (no space left on device)
lol , its a 128 GB SSD
2021-08-21 00:48:04.176 [ERROR] [d4j.internal.RRD4jPersistenceService] - Could not create rrd4j database file '/var/lib/openhab/persistence/rrd4j/HUE_Wohnkuche_TV_Lowboard_Farbtemperatur.rrd': /var/lib/openhab/persistence/rrd4j/HUE_Wohnkuche_TV_Lowboard_Farbtemperatur.rrd (No space left on device)