BTRFS can and will eat your CPU and MEM

Keywords

Debian 10 64bit AMD homebuild NAS
- Only 4gb of RAM
- Shoot yourself in the foot without swap please (when the thing is busy)
- Gigabyte D525TUD with Intel Atom D525 @ 1.8GHz 64bit quadcore CPU
BTRFS filesystem for snapshots and data integrity
btrfs-cleaner kernel process
"hack" -> btrfs quota disable /data
btrfs stats (e.g quota groups) use qgroup feature which seems to be unstable in kernel 4.14 mainline, no clue i'm affected as my debian runs 4.19
https://btrfs.wiki.kernel.org/index.php/Quota_support
https://lore.kernel.org/linux-btrfs/YeVawBBE3r6hVhgs@debian9.Home/T/
https://community.netgear.com/t5/Using-your-ReadyNAS-in-Business/btrfs-cleaner-frequently-stuck-at-100-CPU-after-6-4-0-upgrade/td-p/990419/page/2
https://github.com/digint/btrbk
https://wiki.gentoo.org/wiki/Btrbk