> On Nov 7, 2013, at 11:46 AM, Andrew Berg <robotsondrugs at gmail.com> wrote: > Correct. This is why ZFS support cannot be in the Linux kernel itself (unless it were completely reimplemented from scratch). No. It means that ZFS cannot be shipped as a binary which combines it and code under the GPL, such as the Linux kernel. It does not mean that ZFS may not be used as a binary kernel module. While ZFS first came to Linux via FUSE, the Lawrence Livermore national lab is funding ongoing development of ZFS in-kernel. This work is distributed as source, in compliance with the CDDL. For Ubuntu, one adds the PPA to /etc/apt/... and the source is pulled in and automatically compiled as necessary when the kernel is upgraded. A similar mechanism is available for RedHat & derivatives. > >> Apparently, ZFS was developed by Sun Microsystems which was bought out by >> Oracle. So there is an Oracle version, called ZFS, distributed under the >> CDDL, and there is a "truly open-source successor," called OpenZFS, also >> distributed under the CDDL: >> >> http://en.wikipedia.org/wiki/ZFS >> http://en.wikipedia.org/wiki/OpenZFS >> >> I'm not sure how they differ. In this thread, when people wrote about >> experiences with ZFS, were they really talking about ZFS or OpenZFS? Or >> are they almost indistinguishable functionally and in terms of >> reliability? > Oracle closed the ZFS source code and they have their own version with a few new features like encryption. This version is proprietary and > exclusive to Solaris. So far, I agree with the block of text above but not this: > OpenZFS seems to be a new name for the open source version developed and maintained mainly by the Illumos project (the OpenSolaris family of > operating systems - e.g., OpenIndiana). OpenZFS is a marketing label that covers the increasing coordination between the Illumous folks, the FreeBSD community & the http://zfsonlinux.org folks. > At least one of the principal architects of ZFS, Matt Ahrens, left Oracle and is heavily involved in > the OpenZFS project. This version has a different set of new features, and the zpool version is 5000 to avoid confusion with the Oracle > version, which continued from 28 (it is in the mid 30s now). OpenZFS also refers to the current project underway to make ZFS easier to > support for many platforms. Yes to above, but no to below: > Because of the different feature sets, the two are mostly incompatible, though it may be possible with the feature flags feature of the open > source ZFS to limit yourself to a common set of features. I've used 2 of the 3 open source ZFS code sets. I kept my version of ZFS at 28 so I could switch easily. Soon, I'll upgrade to version 5000. From then on, though, the whole point of "feature flags" is to try to maintain as much interoperability as possible. > I'm pretty sure most people outside the Oracle Solaris world refer to the open source version these days. > Agreed. Thomas