LinuxWorld said that Sun's ZFS filesystem from OpenSolaris has been ported into a server or daemon program that runs on Linux.

ZFS, like the rest of OpenSolaris, is only available under Sun's Common Development and Distribution License for about two years, which means it cannot be part of Linux, which is under version two of the GNU.

Now Ricardo Correia has developed a system which uses a technology called Filesystem in Userspace (FUSE), introduced in the 2.6.14 kernel.
 
Correia's project, NTFS-3g, has managed to get several users running and even booting from a ZFS volume.

More here.