It’s beginning to look like Apple has cut the promising ZFS file system technology from even basic read/write inclusion from OS X Snow Leopard and OS X Snow Leopard Server. All previous mentions of ZFS have been removed as you can see (or not see more accurately) here, here and here. This is about as explicit as it gets. Apple lists the file systems for OS X Snow Leopard Server and ZFS is not there. (Somebody even already updated the Wikipedia page on ZFS already to reflect this.)

My guts tells me Apple made the decision for two interrelated reasons:
1) They want to keep Snow Leopard clean and MORE stable, not less stable because of new features…and file systems are a lot of work…per the recent WWDC Keynote.
2) ZFS is just not ready for prime time in production environments and Apple’s file system team realized this. ZFS has not itself been finalized and Apple’s going to have to do a lot of customization work to make it fit into OS X cleanly. This probably also means it will NOT be compatible with any other ZFS deployments / versions. So much for ZFS as a panacea.

Furthermore, for ZFS to be really useful for OS X customers, Apple will need to do the work to make it compatible as a boot disk which will require even more work and customization and Apple will also need to hide all of the brutal command line complexity and zpool crap and normal RAID levels that characterize ZFS. Getting ZFS to be easy to use is another ball of wax altogether! I bet that will take Apple 2-3 years minimum. In other words, kids please don’t hold your breath for ZFS.

Wow! Isn't this fun and easy! The dark side of ZFS...

While I think ZFS is extremely promising I get really concerned when I hear talk about it in mythical and impossibly optimistic savior-esque terms. In reality, it’s got a long way to go and most people only have such a positive impression of ZFS because they’ve never worked with it. Once you have, it tempers your enthusiasm about 50%-95%. Then again, HFS+ is pretty much ancient history at this point and could not be any less stable (particularly with external storage–needing to dismount? ahem?), so I think all OS X customers are long overdue for something bright and shiny.

My two Drobos I have running at home keep my data safe and don’t require me to understand the ZFS diagram shown. And when ZFS does replace HFS+ in OS X  I am betting Data Robotics will make Drobos 100% ZFS compatible. Until then, I don’t really feel the need to run ZFS just yet. And remember folks, even if you are running ZFS that does not absolve you from needing offsite storage…