Apple's official project of porting ZFS to Mac OS X has been cancelled.
In a simple message posted by MacOS Forge, Apple stated only "the ZFS project has been discontinued. The mailing list and repository will also be removed shortly."
ZFS is an advanced file system and logical volume manager originally created by Sun Microsystems. The file system boasts features such as support for high capacity storage devices, continuous integrity checking, automatic repair and integration of file system and volume management.
Apple's interest in ZFS stemmed back to initial discussions with Sun to use ZFS as a file system in Mac OS X. By 2007, a read-only port of the file system was created and command line support was added to Leopard.
However, the merger between Oracle and Sun Microsystems in April 2009 saw Apple back away from the technology. This was largely rumored to be because Oracle already owned an advanced open-source file system, BTRFS, which upon merger with Sun put the future of ZFS at risk.
By June 2009, all mention of ZFS disappeared from Apple's website and all code was removed from developer builds.
Apple now holds an unfinished file system that, according to rumors, could encounter patent issues with the newly merged Sun/Oracle should they bring it back to life.
No announcements have yet been made as to whether Apple intend to port Oracle's BTRFS to Mac OS X, or whether they will simply continue to build features into the existing HFS+ file system.