We have had access to the private beta of this ZFS support on Linux, which does not use FUSE (File-system in User-SpacE) and unlike the current Lawrence Livermore National Laboratory ZFS port it does have POSIX support. But due to licensing incompatibilities between the Sun/Oracle CDDL and the GNU GPL, this ZFS support cannot be merged into the mainline Linux kernel so it must live separately from the tree even though ZFS is there on OpenSolaris and also on FreeBSD.
We originally reported on this native ZFS Linux work back in August and then this week was when we published the file-system performance tests comparing ZFS to ZFS-FUSE, EXT4, XFS, and Btrfs. We also tossed in some results from ZFS on OpenSolaris from the same test system.
Our coverage has led to a flood of interested users hitting up KQ Infotech even though the performance of this module right now may not be up to par with EXT4/Btrfs/XFS. Thus it's exciting to see them opening up their ZFS beta. Anyone can go to their ZFS product page and fetch the modules. Unfortunately though it does require signing up a small registration form to gain access to the packages, but at least they're freely available to the public at this point.
The ZFS kernel module is presently available for Fedora 12 with the Linux 2.6.31/2.6.32 official kernels, Ubuntu 10.04 on their desktop and server 2.6.32 kernels, and Red Hat Enterprise Linux 6 on the Linux 2.6.32 kernel. The Linux ZFS file-system is also only compatible with x86_64 architectures. As was mentioned this week, KQ Infotech plans to have the ZFS support working on Ubuntu 10.10 with the Linux 2.6.35 kernel by the time of their module's GA release.
For those wanting to see the source-code to the ZFS module and related dependencies like SPL (the Solaris Porting Layer module for bringing some bits of Solaris to the Linux kernel) and the user-space utilities, which are based upon the original LLNL ZFS work, here's a hint: checkout the KQ Infotech's RPMs for Fedora 12 as the source RPMs are bundled there.