> ZFS can be unstable if not fed enough RAM.
--I have seen ZFS (FreeBSD and Linux) be "stable" with ~2GB of RAM, as long as you are using a 64-bit OS. In my experience, these days ZFS only needs lots of RAM if you are doing de-duplication - although this can be gotten around to a certain extent if you use an SSD drive for L2ARC; it will just be slower. Maxing out your RAM is recommended if you want max speed and you can afford it, but there are other ways. As long as you're not doing de-dup and not expecting miracles; my ZFS backup/fileserver only has 6GB of RAM and is doing fine running Ubuntu 14.04-64-LTS.