I believe this issue is much more wide spread than it appears - I found this on the unraid subreddit and decided to poke around my server. Currently loop2 is writing over 2gb in under 10 minutes to my unencrypted BTRFS cache pool.
Unraid: 6.8.3
Added a new samsung 860 1tb ssd to my btrfs pool 4 months ago:
22.01 TB (47269069408)
3383 (4m, 18d, 23h)
I'd rather not have to run XFS and or modify unraid beyond what is supported. Hopefully we can get a official update on this and or a fix soon as this is causing excessive writes to my ssds - thus reducing their life and possibly causing unforeseen damage.
Referenced subreddit post:
https://www.reddit.com/r/unRAID/comments/ggbvgv/unraid_is_unusable_for_me_because_of_the_docker/