Rapid increase in Influx database storage size

I have the impression that the storage size of my influx database is rapidly increasing since my update of openHAB in mid December 2023. Has anyone noticed something similar? How to decrease the database size? How to find storage hungry items?

Here are some background information:

  • I made a backup of my openHAB 3.2 conf folder
  • I made a backup of the influx database (influx backup mybackup -t xyz..==)
  • installed fresh Xubuntu 23.10, OpenHAB 4.0.4, InfluxDB 2.7.4 etc. to my machine
  • setup the influx with the previous token and restored the old data (influx restore mybackup --full)
  • made all necessary changes to the OpenHAB configuration files (added UoM etc.) to get it running again
  • added some new items after the upgrade (just some temperature values, by copy’n’paste of old items)
  • everything is running fine, in charts I see persisted data from before update together with new data from after the update, So I think that the configuration itself is OK.
  • The retention policy for my openhab bucket is 365 days.

The backup has a size of 18GB. After the restore it was not much larger on the disk, but in the 6 weeks since then it more than doubled in size (today 38.5GB). My impression is that it increases rapidly since the update. How can I check what’s going on? How can I find out which data is big (e.g. stored as string instead of number, stored too often)?

Can you compare the content of two backups e.g. compare sizes of two items ?

I’m experiencing something similiar, but for me it started in November.
I know, I did an update on the 4th of November, but I don’t know which one. Also it is possible, that I added items to the persistence at that time, but I have no idea how to figure out as well. Also an update of the Influx DB itself during that time can be possible.

Below are folder sizes from the influx DB with last change date, so there is a huge change since then.

Total size for 3 years:

I checked which data I persist and saw that I have many strings, which I believe is not that good for InfluxDB. However the greatest problem where some Images from my Doorbird stored. Those were in the persistence from the beginning, but I believe they were never actually put into the DB. It might be that this behaviour changed, because when I started deleting those images for the timeframe from 1st of November until now, the DB first got even bigger:
and after deleting all of them I could find it was very small in comparison:
However, I remember having like 750 MB of data for quite a while, so there still needs to be something taking up more space than it used to be. Maybe some of the strings items?