More evidence: "Mac OS X Leopard (Build 9a321) features support for ZFS. The rumors were true, you can create disk images with a ZFS filesystem, well at least in theory, because Build 9a321 is far away from being stable. The DiskUtility itself crashes again and again. Trying to create an actual ZFS image produces kernel panics. There is no pool support to create stripes, mirrors or even RaidZ in DiskUtility yet. It seems that all the other rumor sites stopped right there, which is why we had to set up this website to show you how well ZFS is already implemented. We show you what works and what doesn't. After reading you will know what the deal is, with ZFS and the upcoming Mac OS."