Ummm... keep in mind that Apple is looking at building a large data center in the Carolina's. My bet is that if Apple could, they would likely prefer to eat their own dog food so to speak. Snow Leopard Server, IMHO, would probably be the chosen weapon of choice. Just because customers aren't currently leveraging OS X in those markets doesn't mean that Apple wouldn't like to be there or prefer to use what it knows for vertical integrations with their own products (vs. try to manipulate an OS that isn't of their own design). They just need the key elements to provide the relevancy that they need and while that might not be their forte today, it could very well be in their repertoire tomorrow.
It depends on the pragmatics of what they're attempting to attack. What they've learned in their experiences might allow them to improve upon what ZFS was trying to achieve and what would benefit most of it's users. Consider that it didn't take Apple nearly as long as what Sun has taken on ZFS to make HFS and HFS+ work. True, both of those file system's aren't nearly as complex or all encompassing as ZFS but the question that begs to be answered... does anyone truly need all of that which ZFS is providing and/or can a simpler solution be conjured that provides the vast majority of features without all of the achilles heels/hurdles to a practical solution that scales to fit within the Mac OS X operating system (and potentially other systems) more effectively?
Consider that even Sun has run into issues with trying to get ZFS to work within bootable environments and how even more daunting it has been to just graft ZFS onto other environments, including presumably OS X, ZFS might not nearly be "The Holy Grail" everyone has seen it as. True there's a lot to like/love about ZFS... but if it's flaky and temperamental and/or licensing is draconian or prohibitive... or if it muddies the user experience and requires them to have knowledge of when to use file system x vs. file system y, it's not intuitive to the primary target market (i.e. personal computers). It is at that point then that I'd pursue/consider another option. When Apple jumped on KHTML to make Webkit, the framework was not nearly as embraced as it is today, not as robust, nor as pervasive. Now there's browsers on just about every platform being based on Webkit (including Google's movement towards ChromeOS as an OS platform in itself), even KHTML itself has shifted to reusing bits of Webkit vs. sticking to their original fork.
Also consider the fact that Apple has tapped into open-source alternatives to closed source/licensed programs and that there is an open-source competitor to ZFS. Also consider that Oracle was a key-supporter in an alternative to ZFS as well called Btrfs which is available under GPL for Linux.
http://liquidat.wordpress.com/2007/08/07/interview-chris-mason-about-btrfs/
http://www.codestrom.com/wandering/2009/03/zfs-vs-btrfs-comparison.html
It doesn't hurt that Steve Jobs is longtime friends with Larry Ellison of Oracle...
So this singular file system engineer might be tasked with a team of developers to figure out how to look into Btrfs or perhaps simply take what's available in Btrfs and work it into an Apple-specific solution. With Ellison and Co. purchasing Sun, this could either mean "the end" of ZFS (maybe even within Oracle-owned Sun which has moved glacially slow since announcement, the tech world moves at the speed of light... it's not like Sun has ceased development of ZFS but, by the time ZFS licensing via an Oracle-owned Sun becomes favorable to Apple... Btrfs could potentially be on-par or ahead, esp. with support of another partner [i.e. Apple] working on it) or a decisive shift to something else.
Personally, for Apple's needs... Btrfs's GPL licensing might well be better suited to Apple's needs, even though admittedly Btrfs isn't nearly as far along as ZFS. Then again, as long as it's taking for the Sun/Oracle deal to go through... the favorability of that arrangement longterm obviously spells potentials for Apple to jump into ZFS (assuming Ellison and Co. don't just elect to scrap it) but, only if the alternatives haven't caught up or surpassed ZFS by that point. The great thing about tech is... if the time comes and ZFS is still there, Apple can dust off what work they've done and reopen the project. Otherwise, it could benefit Apple to see where they can take Btrfs or an Apple-engineered spin-off/fork of the Btrfs codebase into Apple's own focus.
It is not confirmed that MS has given up in any stretch. The thing with MS is that some development work within their confines has taken epic amounts of time to get done. Look at their track record with OS releases and you'll see that even there, MS hasn't exactly been the company of accord when it comes to shipping on or near dates. That said, Windows 7 has seemingly pointed towards MS turning the corner vs. other projects in the past so it might be a changing of the guard in that vain. That noted... WinFS has never been said to not be in the cards, just that it didn't make it into Vista (which as an OS was pretty much scrapped and restarted halfway through the whole Longhorn development) nor Windows 7, but it could very well come into play down the road.
