I haven't done it on heavily enough MySQL servers to really tell you - but on "typical" installs there is no noticeable difference. I'd say add a bit of extra

I haven't done it on heavily enough MySQL servers to really tell you - but on "typical" installs there is no noticeable difference. I'd say add a bit of extra RAM for ARC overhead you wouldn't usually, and of course invest in SLOG devices. ZFS is never going to win any speed races, but what we gain in snapshotting/rollback/trivial remote backups makes it a great fit for many of our pgsql/mysql installs.