system drive full

I have a new installation of OMV and added some dockers.

I had problems logging in to the server webgui.

Looking in the forum the drive of 120 Gb was probably full and it was.

I was able to use docker system prune -a to free some space but this only freed 1,0 Gb.

I uninstalled docker and removed the /var/lib/docker folder this only freed a couple of more Mb total free space is now 1.4Gb.

I have daily backups of the system drive with the backup "dd full disk" to another drive. The backups from last week are around 32 GB and yesterday the backup was 48 Gb.

I would like to prevent a new installation.

1. How do I restore a backup?

2. How can I prevent the drive from filling up? How can I find out what is filling the drive?

3. I used a 120 Gb drive because I thought this was enough for a few dockers (URbackup, heimdall, Portainer, Yacht, Handbrake, MakeMKV)

There was a long string in the srv that didn't match an external drive.

Thank you very much, just found 98 Gb of space.