> For the complete documentation index, see [llms.txt](https://book.bsdcn.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://book.bsdcn.org/ask/flat/chapter-28-the-zfs-file-system/di-28.1-jie-zfs-li-shi-yu-xian-shi.md). # 28.1 ZFS History and Reality ZFS originated from Sun Solaris, was open-sourced under the CDDL license in 2005, and was imported into FreeBSD in 2007. After Oracle acquired Sun and terminated public development of ZFS, the open-source community launched the OpenZFS project in 2013 to continue its development. In 2020, OpenZFS 2.0 merged the FreeBSD and Linux ZFS codebases, unifying storage features including Copy-on-Write, Snapshot, End-to-End Checksum, and Self-Healing. ## ZFS Development History: From Solaris to OpenZFS ZFS was originally developed by Sun Microsystems to replace the UFS file system on Solaris (formerly known as SunOS). One of the key developers of SunOS and BSD Unix was Bill Joy, who was also one of the founders of Sun. SunOS was initially based on BSD Unix and later transitioned to SVR4 (Unix System V Release 4, the version co-developed with AT\&T). The ZFS source code was integrated into the Solaris development trunk (revision 789) on October 31, 2005, and was subsequently released as open source under the CDDL (Common Development and Distribution License) on November 16, 2005, as part of OpenSolaris build 27. ZFS was imported into the FreeBSD source tree in 2007. FreeBSD 7.0-RELEASE (February 2008, pool v6) shipped it in an experimental state; FreeBSD 8.0-RELEASE (November 2009, pool v13) declared it production-ready. After Oracle announced the acquisition of Sun in April 2009 (completed in January 2010), the Solaris project (renamed Oracle Solaris) and ZFS (renamed Oracle Solaris ZFS) entered a closed-source development model. The OpenSolaris Community Board dissolved itself in August 2010 (revision 13149; at the time of dissolution, the ZFS pool was at [v28](https://github.com/freebsd/freebsd-src/commit/572e285762521df27fe5b026f409ba1a21abb7ac)). The primary community developers of OpenSolaris migrated to the new [illumos project](https://github.com/illumos/illumos-gate) fork. From that point onward (v28), Oracle Solaris ZFS and the community version diverged. Currently, illumos follows a development model similar to the Linux kernel, having spawned over a dozen distributions including OpenIndiana and OmniOS. However, its average annual commit count is approximately 150, indicating a significant decline in development activity. In July 2010, FreeBSD adopted ZFS pool v15 (merged into 9-CURRENT), which was the version distributed with Solaris 10 update 8 (Solaris 10 10/09) in October 2009. In November 2011, Oracle Solaris 11 was released, upgrading the ZFS pool to v33 (Solaris 11 Express 2010.11 was at v28). On January 12, 2012, FreeBSD 9.0-RELEASE supported ZFS pool v28. See: Finally... Import the latest open-source ZFS version - (SPA) 28\[EB/OL]. \[2026-03-26]. . Three years after the shutdown of OpenSolaris (2013), the OpenZFS project was officially established, unifying the open-source development of ZFS (prior to this, the ZFS on Linux native kernel module project had been initiated by Lawrence Livermore National Laboratory in 2008, while the FUSE-based ZFS-FUSE project began in 2006). Due to the closed-source development of Oracle Solaris ZFS, OpenZFS has difficulty maintaining compatibility with Oracle Solaris ZFS. "When the times are favorable, heaven and earth work together; when fortune fades, even heroes cannot act freely." (\[Tang] Luo Yin, "Chou Bi Yi"). Since almost all cloud platform vendors and virtual machine platforms only support Linux, illumos could no longer gain support. Delphix, the primary developer of new OpenZFS features (Perforce Software completed its acquisition of Delphix on March 25, 2024), consequently migrated its operating system from illumos to Linux, essentially abandoning investment in illumos. Even Oracle Solaris itself has entered maintenance mode (version 11.4's lifecycle extends to 2037). Oracle ZFS transitioned to the enterprise storage solution [Oracle Storage](https://www.oracle.com/storage/#zfs-storage-appliance). Feature updates for the illumos version of ZFS have become increasingly rare (its primary development force remains OpenZFS), and the difficulty of maintaining this version of ZFS in FreeBSD continues to rise. New ZFS features typically had to be merged into illumos first and then backported to FreeBSD. However, illumos development has essentially stalled. In August 2018, the FreeBSD Project began researching how to migrate FreeBSD ZFS from illumos to the upstream OpenZFS. OpenZFS was merged into FreeBSD-CURRENT in August 2020 and was officially released with FreeBSD 13.0-RELEASE (April 2021). "The ZFS implementation is now provided by OpenZFS. [9e5787d2284e](https://cgit.freebsd.org/src/commit/?id=9e5787d2284e) (sponsored by iXsystems)" replaced the OpenSolaris/illumos version of ZFS. This migration reconnected FreeBSD with the mainstream ZFS open-source ecosystem. Currently, the top contributor by commit count in OpenZFS is from the Lawrence Livermore National Laboratory (LLNL). OpenZFS development is driven by multiple organizations, with major contributors including LLNL, Klara Inc., iXsystems, and Delphix. LLNL's core mission is to ensure the safety, reliability, and effectiveness of the U.S. nuclear deterrent. Sun means "sun." As the sun sets in the west, it also rises in the east. This metaphor aptly encapsulates the journey of ZFS migrating from the Sun ecosystem to a broader open-source ecosystem. ### References * Matuška M. ZFS in Open Source Operating Systems\[EB/OL]. (2011-02-05)\[2026-04-02]. . A FreeBSD project report after Oracle's closure of source code, documenting key milestones and developers. * FreeBSD Project. Comprehensive changes for vendored openzfs\[EB/OL]. (2020-07-29)\[2026-04-02]. . Documentation of the code review process for switching to OpenZFS. * FreeBSD Project. 9e5787d2284e\[EB/OL]. \[2026-04-02]. . Migration commit record on GitHub. * OpenZFS Project. History\[EB/OL]. \[2026-04-02]. . Official history of the OpenZFS project. * OpenZFS Project. Add support for FreeBSD\[EB/OL]. \[2026-04-02]. . PR submitted to OpenZFS for FreeBSD support. * Dimitropoulos S. Debugging ZFS: From Illumos to Linux\[EB/OL]. \[2026-04-02]. . Delphix's migration concentrated ZFS development on the Linux platform. * Red Hat. Red Hat and Labs Build the World's Most Powerful Supercomputer\[EB/OL]. \[2026-04-02]. . Introduction to LLNL's collaboration with Red Hat and large-scale Linux usage. * Oracle. Oracle and Sun System Software and Operating Systems Oracle Lifetime Support Policy\[EB/OL]. \[2026-04-02]. . Oracle product support lifecycle document, page 41 for Solaris. * OpenZFS Project. Announcement\[EB/OL]. (2015-04-15)\[2026-04-16]. . Records that the OpenZFS project was officially established on September 17, 2013: "Today we announce OpenZFS: the truly open source successor to the ZFS project." * Burt J. Oracle Completes Sun Acquisition\[EB/OL]. (2010-01-27)\[2026-04-16]. . Records that Oracle completed its acquisition of Sun on January 27, 2010. * NERA Economic Consulting. US DOJ and DG Comp Clear Oracle's Acquisition of Sun Microsystems\[EB/OL]. \[2026-04-16]. . Records "On 20 April 2009, Oracle and Sun announced that Oracle would acquire Sun" and "On 27 January 2010, Oracle completed its acquisition of Sun". * Perforce Software. Perforce Software Completes Acquisition of Delphix\[EB/OL]. (2024-03-25)\[2026-04-17]. . Records that Perforce completed its acquisition of Delphix on March 25, 2024. * Jude A. The History and Future of OpenZFS\[EB/OL]. (2020-03)\[2026-04-17]. . AsiaBSDCon 2020 presentation, clearly distinguishing ZFS-FUSE (the presentation defines the LLNL-involved ZFS-FUSE userspace implementation as starting in 2008; the ZFS-FUSE project mentioned in the main text as starting in 2006 refers to its earlier independent development phase) from the ZFS on Linux native kernel module project (initiated by LLNL in 2008). LLNL, Lawrence Livermore National Laboratory. ## Licensing From the perspective of intellectual property and open-source licensing, ZFS could not be directly included in the Linux kernel tree due to fundamental license incompatibility. The Linux kernel uses the GPLv2 (GNU General Public License version 2) license, a strong copyleft license that requires derivative works to be distributed under the same license; ZFS uses the CDDL (Common Development and Distribution License), which also contains copyleft provisions but whose scope of contagion is limited to CDDL-licensed code files. The two licenses have substantive conflicts in their copyleft contagion scope and rights/obligations requirements, making it impossible to resolve the compatibility issue through dual licensing. Consequently, ZFS could not be included in the main Linux kernel tree. > **Discussion Question** > > Read the original text or translations of the GPLv2 and CDDL licenses. > > 1. Explain why the two licenses conflict. > 2. The Free Software Foundation states that any out-of-tree module is non-compliant, and the Ubuntu ZFS module is one such example. Does this prove that the entire Linux kernel is licensed under GPLv2? > **Tip** > > ZFS has multiple implementations; for a feature comparison table, see: Feature Flags\[EB/OL]. \[2026-03-26]. . --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://book.bsdcn.org/ask/flat/chapter-28-the-zfs-file-system/di-28.1-jie-zfs-li-shi-yu-xian-shi.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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