On Wed, 12 Feb 2020 23:37:26 -0700 Chris Murphy <lists@xxxxxxxxxxxxxxxxx> wrote: > I have fstrim.timer set to run fstrim.service once per week, and that > reports sane (expected) values each time. But, it also tends to happen > soon after a fresh boot or wake from S3. I believe Btrfs now[1] tracks which areas have been trimmed already during the current mount and does not re-trim them again, like ext4 does since a long time ago. In case of ext4, for your scenario the first trim would return 91GB, and the subsequent ones (assuming no FS activity) would trim 0 bytes. But if the above is indeed the cause, then I'm not sure why it still always retrims about 3.6 GB or 11 GB for your other machine, even with no writes or deletions. [1] https://patchwork.kernel.org/patch/11254859/ -- With respect, Roman
