I would worry a little about going above 90% space usage. ZFS slows down fairly dramatically when it starts running out of contiguous space and there is no defr

I would worry a little about going above 90% space usage. ZFS slows down fairly dramatically when it starts running out of contiguous space and there is no defragmentation tool. On the other hand it's not that hard to export and re-import a ZFS file system from a workstation or laptop to defragment manually - it's harder to do that with a NAS with lots of drives when you don't have a second set of drives just hanging around.