Re: Btrfs best practices: defrag?

[piorunz <piorunz@gmx.com>]

I'd like to add question to this topic.

Is it safe & recommended to run autodefrag mount option in fstab?
I am considering two machines here, normal desktop which has Btrfs as
/home, and server with VM and other databases also btrfs /home. Both
Btrfs RAID10 types. Both are heavily fragmented. I never defragmented
them, in fact.

Running manual defrag on server machine, like:
sudo btrfs filesystem defrag -v -t4G -r /home
takes ages and can cause 120 second timeout kernel error in dmesg due to
service timeouts. I prefer to autodefrag gradually, overtime, mount
option seems to be good for that.

My current fstab mounting:

noatime,space_cache=v2,compress-force=zstd:3 0 2

Will autodefrag break COW files? Like I copy paste a file and I save
space, but defrag with destroy this space saving?
Also, will autodefrag compress files automatically, as mount option
enforces (compress-force=zstd:3)?

Any suggestions welcome.

--
With kindest regards, Piotr.

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