I sort of love Ubuntu ZFS on root and sort of don't.
I have a lot of complaints.
(1) Almost completely missing documentation. The entire knowledge base is centered around Didrocks blog.
- How do you add datasets to zsys?
- How do you backup/restore this?
- zfs complains that the pools can be updated to use new features but it's not clear if this is safe.
- Unclear about how zfs volumes were setup. How frequently does this scrub and trim? (not very)
(2) Poor handling of file systems with lots of changes. This sounds like an edge case, but if you use steam to manage a games library and do some video or photo work on the side, you're going to find a lot of snapshot induced storage bloat. I've had to reduce the snapshots held in zsys.conf.
(3) bpool size is too small for the kernel image rotations. I end up having to manually remove old kernels and snapshots. Complaints of this are extremely common. You can, with some pain, replace the bpool with a larger one.
(4) Unclear behavior in recovery mode. If I go back to an early snapshot, is the current dataset still fine? What happens if I make a change? -Confused-
(5) Snapshot names are cryptic. I would have hoped for something like an ISO timestamp and a simple iterator.
(6) No configuration options at setup. Going back to the above, having a sane default is/would be great, but adding ZFS options and setting the sizes of bpool and dealing with complex zfs pools would be useful in the installer.
Overall, zsys seems like requires an understanding of ZFS to run with confidence that you won't suffer some catastrophe in an edge case. It so opaque that it's a big tradeoff to commit to zfs on root, as you need to really understand ZFS to use it, but at the same time, if you're that into ZFS, you'll find it frustrating.
