No, I didn't test it on ZFS. Sorry for asking, but is there any reason to run DBMS (which I would like to remind has a build-in compression) on ZFS which itself is a small DBMS? Sounds like too much unnecessary overhead to me.
Several reasons. Snapshots, Cloning, Replication. Customized record sizes per database. There are many good reasons to run PG on ZFS and almost everyone does. Except the MySQL/Linux crowd. The rest of have moved on from the pain of the well worn FS's of the distant past.
Very interesting. For some reason I always thought that no one runs PostgreSQL on ZFS. If it's not a secret, what company uses PostgreSQL on FreeBSD like this?
Has this even been tested on zfs?