I found an old ZFS disk laying around the other day (a few years old.. from when I was playing with zevo community edition ZFS and I had forgotten what I had st

I found an old ZFS disk laying around the other day (a few years old.. from when I was playing with zevo community edition ZFS and I had forgotten what I had stored on it) and I was interested in trying https://openzfsonosx.org https://openzfsonosx.org so I installed it and mounted my disk up. It worked like a charm. I was pretty impressed. I kind of screwed myself over though because I to do a bunch of file cleanup that I was hoping to perhaps roll back if it didn't go well so I created a snapshot and then got to work with some copying… I wasn't paying attention and I ended up running out of space on the disk. The way ZFS snapshots work is that ZFS still does what it would normally do on a copy: writes data, then verifies the write is completed before deleting the old data. When there is a snapshot, it just skips the second step and leaves the old data around. This is how snapshots have zero performance impact on data write. Turns out that I couldn't even delete the old snapshot (or rollback the new one) because I didn't have enough space to make any changes to the disk. I couldn't even delete files because they would stay in the snapshot. Aha! I can add a disk to the pool! So I added a small disk to the zpool and then I could delete the snapshot ok. However, I forgot that you can't remove a disk from a zpool. I ended up having to move the data to another disk, drop the entire zpool and recreate it, and move it back. Honestly, everything worked rather well except for forgetting a few of the limitations of ZFS. Given how often I have issues with HFS+ I really think it's pretty tempting for OS X.