Btrfs + Luks persist

Hi, I am using a btrfs + luks configuration which I made last year. Recently I have been seeing a new subvolume called /persist in the btrfs documentation and was wondering what it does and considering if I should implement it. Can someone explain to me in simple terms why I’ll need persist partition?

Perhaps it is because a subvolume mounted at /persist is often used by people using something like GitHub - nix-community/impermanence: Modules to help you handle persistent state on systems with ephemeral root storage [maintainer=@talyz].

Where in the documentation are you seeing it?

The install with encryption section of this Btrfs - NixOS Wiki

Ah yeah, the person who wrote that was likely using a impermanence setup. Probably should remove that line in wiki for clarity.