Disclaimer: Yes, I do regularly back up my data. But hadn't I backed up my data, I nearly missed a full-disk data loss.
I decided to try out creating a RAID server. I needed something lightweight, which is why I decided to test out OpenMediaVault rather than FreeNAS.
During installation, I expected to be asked about which partition I would like to use with my installation. The installer indicated it was about to show a list of partitions.
Instead, the installer decided to format the first thing it can find to ext4. I quickly shut off my PC.
It turns out that a partition I used mostly for temporary data got re-formatted to ext4.
The installer lied to me when it said it was about to show me a list of partitions.
I decided to warn the community of this potential hazard.