Developers at the Lawrence Livermore National Laboratory have successfully ported Solaris' ZFS file system to Linux.
The problem has been the CDDL. The CDDL is incompatible with GNU Public License that the Linux kernel uses.
As a result, ZFS has to be downloaded, compiled and run in user space rather than distributed with the Linux kernel.
So why doesn't Oracle, which now owns the ZFS copyright, just change the license to the GPL?
"We have been working on this for some time now and have been strongly urging Sun/Oracle to make a change to the licensing. I'm sorry to say we have not yet had any luck. However, we did feel it was time to move our efforts to a public forum," Open Source Developer Brian Behlendorf said.