ZFS & Mac OS X: A Future Imperfect

My initial work with ZFS on my OS X laptop has left much to be desired. Let’s just say that on FreeBSD the code has been worked on more extensively and that it feels much more mature compared to the work that Apple engineers have done on OS X integration with ZFS.

The main snag is how OS X deals with mount points. Let’s say that you start out with /Users residing on your HFS+ partition and then create a new ZFS filesystem, and attempt to set the mountpoint to /Users. Well, the UNIX underbody understands this just fine and you’ll open up a shell into the ZFS filesystem. Finder and other applications might not pick up on the new mount and continue to reference the HFS+ volume. It’s a bit messy if you aren’t careful.

The other thing to be aware of is that you can’t just shrink down your HFS partition, then create a ZFS partition out of free space or convert a HFS partition to ZFS. The system will not realize that the ZFS module needs to be loaded on boot, and you could be stranded at the login screen if your home directory resides on a ZFS partition. It is extremely important that you use the diskutil command line utility to split your volume into an HFS volume and a ZFS volume.

I’m left a little disappointed and a little worried about the future at Apple. Especially when all mention of ZFS has been excised from product materials. Combined with Snow Leopard’s read only support for UFS volumes, I begin to worry that Apple is going to just sit in the dark and pretend that everything is just fine with HFS.

You would think that a few engineers who get PAID to integrate ZFS into the core of the OS would do work that would exceed work done by a few volunteers in the FreeBSD community. The FreeBSD community has seen the writing on the wall and has spent time and energy preparing themselves for a filesystem change. Linux developers might have objected to the licensing of ZFS, but they knew that ZFS represented a major change in storage management and began their own efforts to develop a similar solution in the form of btrfs. Filesystem development in the past few years has become very fluid, and I don’t think Apple realizes this.

I’m not about to give up and go back home, I’m running ZFS on my laptop as we speak, but I worry that I could be stranded if Snow Leopard doesn’t reveal any progress regarding ZFS.