What is eating my storage?

Problem Description
I check my Freedombox daily using Cockpit. Both for updates and to make sure it is still up and running. I noticed that my storage needs are steadily increasing. It increases by approx. 1Gbyte/week. The sd card is 32 Gbyte. As I write this, the storage is up to 8.1 Gb.

I’ve had crashes in the past, and after a fresh re-install and using the most recent backup to get everything back up to speed, this behavior resurfaces every time.

My setup is:

Raspberry Pi 3 Model B Plus Rev 1.3
FreedomBox version 24.13, running from an SD card 32 Gb
installed software: Radicale with default backup options.

How can I find out what causes the steady increase in storage?

How are you set up for the following services whose use of storage depends on how they’re configured:

  1. Logging (System/Configure)
  2. Backups (System/Backups)
  3. Snapshots (System/Storage Snapshots)

See the answers down below:

So logging wouldn’t be an issue because (most) logs aren’t being written to disk. Assuming the amount of data to be backed up remains about the same, storage used would increase until the caps on the number of backups and snapshots are reached, then should level off. To get an idea of where you are on this curve, check the number of backups (System/Backups) and snapshots (System/Storage Snapshots/Manage Snapshots) and how they map to the frequency and caps specified in the configuration.

If you’re currently using 8% of available space, you still have a ways to go before the Snapshots rule to prune back old snapshots to maintain 30% free space kicks in.

I recommend the command-line tool “ncdu” to help find out which folders are taking up the most space.