Technical limits with Jellyfin ?

[TheDreadPirate]

ZFS is a CoW (copy on write) file system. Meaning that when a file is modified it makes a copy of the whole file with the new modifications instead of modifying the existing file on the disk. This isn't a big deal for most things. But for a database where you are making a lot of small changes very frequently to the same file this can result in significant write amplification. Meaning that a small number of small write operations results in a large amount of bytes written. This can be problematic both from a performance perspective and from an SSD endurance perspective.

BTRFS is also a CoW file system.

Having said all of that. My understanding is that the use of journal files by SQLite, and other modern DBs, mitigates these issues. So having your DB on ZFS or BTRFS isn't as bad as it used to be. As long as it is an SSD. Especially if you intend to use the snapshot capabilities of ZFS and BTRFS.