A notice posted today on Apple's ZFS open source project page indicates that the project has been terminated.
The ZFS project has been discontinued. The mailing list and repository will also be removed shortly.
ZFS is an advanced file system developed by Sun that had been ported to Mac OS X and released as an open source project on Apple's Mac OS Forge collaboration site in 2007. ZFS had been rumored to become the default file system for Mac OS X Leopard, but ultimately appeared with only limited read-only capabilities.
Apple's continued interest in ZFS was indicated by inclusion of the technology in its early product description pages for Snow Leopard Server, although the information was subsequently removed from Apple's site and support for ZFS was not included in either Snow Leopard or Snow Leopard Server upon release.
Several sources later indicated that the lack of ZFS support in Snow Leopard was due to licensing issues with Sun, leaving the future of ZFS uncertain, although Sun's pending acquisition by Oracle left open the possibility that the issue could be revisited in the future.
The apparent cessation of Apple's support for the ZFS open source project, however, suggests that the company may have given up hope of achieving satisfactory licensing terms for the technology and redirected its resources elsewhere.
Apple yesterday also posted a new job listing for a file system engineer. While the description includes duties related to "maintenance of existing file systems", it also specifies work in the "design, implementation and support of future file system technologies", suggesting that the company may be expanding its in-house team to develop its own file system technologies rather than pursuing ZFS.
