Where does all the storage go?

Configuration
1

I have a vanilla home assistant instance running on Raspberry PI. I had to do a restore yesterday. I notice after the restore that the disk storage in use has more than halved. Why is this?
Some time ago I had a System Green, it kept slowly filling up and eventually I moved to the RPi as Green isn’t easily expandable without external hard drives/etc and I just don’t want the hassle and power draw of an extra device. I could never find out what was using all the space on the Green and I still can’t on the Pi. It was not the database as I have that well controlled. It was as though there was some “hidden” storage somewhere that I couldn’t see. It seems the same on the RPi.

After this restore, from the point of view of HA all my data and history is there - nothing lost - just less storage used.

Has anyone any suggestions?

(I have put this in “Configuration” as I am hoping it is a configuration issue)

2

There actually literally is, containing the data Home assistant maintains about all devices, entites and and states. But that is just a part of what is there. It could be a number of things, including backups (which I hope you make). But you fail to mention what you consider a lot. Half of something unspecified could in fact be little. And by vanilla you mean no custom integrations or addons, which too might take up space?

But if you must know, make an unencrypted full backup, unpck it and look. That contains about everything your restore added to your vanilla setup.

3

Most is taken up by docker overlay2 folder (the images of all docker containers)