For those interested in the native port of ZFS to Linux, the work being done by LLNL and others continues to advance.
ZFS 0.6.0-rc11 along with a matching release of SPL, the Solaris Porting Layer, were released on Tuesday.
Brian Behlendorf announced the release of ZFS 0.6.0-rc11 with support for ZVOL-based SWAP devices, support for pre-emptible kernels, vastly improved msync() performance, improved behavior under low memory conditions, improved zpool import search behavior, zstreamdump from Illumos, zfs get -t datatype support, and a few fixes.
Some of these ZFS improvements were back-ported from the Illumos project.
More details can be found from the ZFS release announcement