I can't reply to the other reply for some reason, but what they said is indeed what I meant. gitlab.com might be running their Gitaly servers on btrfs or zfs or lvm volumes or whatever, but other customers may be using ext2. Gitlab the company could require customers to only run Gitaly on a specific filesystem, but up to now, they never have, it would be pretty shitty to suddenly change their minds after a decade plus of establishing one expectation, and whoever the developer is who submitted the patch to upstream Git and got a technical blog post out of it has absolutely no power to dictate contract terms to enterprise customers personally and instead did what is actually in their power to do.