[jbronn]

ZFS is released under the CDDL 1.0. The terms of the CDDL (§2.1) grant a "a world-wide, royalty-free, non-exclusive license" for any patent claims "infringed by the making, using or selling of" ZFS now owned or later aqcuired by Sun/Oracle.

Thus, typical ZFS users cannot be sued for infringing on the patents that Oracle holds on ZFS technology. However, this does not preclude third-parties (e.g., NetApp) from pursuing patent claims that they believe are infringed by ZFS -- but this is just as true with any other technology (think MS suing Garmin over FAT in Linux).

Liability for infringement on Oracle's ZFS patents is possible if a user does not comply with the terms of the CDDL. For example, modifying the ZFS source code and distributing it using a license other than the CDDL would be a breach of the license terms (§3.1), and thus forgo any patent license. The Apache 2.0 license has similar terms regarding patent rights.

[Confusion]

  (think MS suing Garmin over FAT in Linux)

OT: That was TomTom, not Garmin