What I'd love is for the L2ARC system built on top of ZFS to be ported as well. That's a killer feature for web applications. Basically, it can extend your cache to include an SSD, but manage that all internally, so you just use your database as usual on top of ZFS and let it handle all the caching and moving less used data from SSD to disk and vice versa, and of course the usual filesystem caching in RAM as well.<p>Though you could get similar functionality by using membase at the expense of being limited to get/set operations (it's a K/V store).