It was used at my old job on a 1TB backup drive, containing lots of hourly snapshots from around 100 other machines that also had btrfs on it (btrfs send). The

It was used at my old job on a 1TB backup drive, containing lots of hourly snapshots from around 100 other machines that also had btrfs on it (btrfs send). The snapshots were also frequently thinned (i.e. only a few of the older ones kept) to make room for new ones. The filesystem broke at least two times in two years when it was nearly full. None of the fixes we found with web searches worked. We went with formatting and copying the backups from another location, losing only a little bit of data that was not too important. That was around 2015-2017, and the version of Btrfs was about what's in Debian jessie.