Tl;dr: I had random errors caused by “no space left on device” due to BTRFS snapshots.
- FreedomBox version: FB 21.4
- Hardware: RaspberryPi 2 Model B
- How did you install FreedomBox?: Official image on a 4G MicroSD card
I was having random errors these recent days, mostly when trying to either access TinytinyRSS or connecting via SSH. TTRSS would not load and result in a HTTP 500 error page pointing me to the ‘status log’ - unfortunately the status log was not available since a login was not possible on the web UI using the provided URL. When navigating to the still running ‘/syncthing’ web UI I was able to get a valid user session and access the status log. It showed “no space left on device” errors.
I shut down the FB, removed the SD and plugged it into another computer. There I was able to delete old BTRFS snapshots and free up a little disk space. These two resource were really helpful:
- BTRFS and free space - emergency response • Oh The Huge Manatee!
- Marc's Blog: btrfs - Fixing Btrfs Filesystem Full Problems
Afterwards I put the SD card back into the Raspi and booted the FB again. All working fine.
As far as I could see the error started surfacing with a major apt upgrade happening. I have automatic updated enabled so it is quite possible that my FB will crash with the next run of unattended-upgraded the coming night.
I am currently considering buying a new SD card (the current one is only 4G) and re-installing my FB using one of the backups I made. I’ll update this post if I encounter any news on this. In my snapshots settings I have set the “keep free” value to 40%, hoping that this helps mitigate this issue.
I hope this helps somebody else. I love my FB and am very happy with the overall experience over the past few years. Thanks a lot to everybody who contributes to making this possible.