I set up a ZFS pool of 8 harddrives under FreeBSD 7.2 a couple of years ago. This pool is storing data, the OS itself runs on a separate harddrive with conventional UFS2.

Now I am thinking about upgrading to the latest version FreeBSD 8.2.

Has anyone gone through upgrading ZFS before ? Can I simply export the pool in the 7 installation and then re-import in the new environment ? Or should I expect any complications ?

In other words: Are newer zpool versions backward compatible ?

FreeBSD 8.2 comes with ZFS version 15. I can't seem to find out what version came with 7.2, but IIRC, that was the first major release that supported it all...


An older pool can be imported with no issues on a newer system - it's completely backwards compatible.

However, it's not forward compatible; once you upgrade to version 15, there's no going back to an older system.

Use the zpool upgrade command to up the pool's version.

  • thanks for the info! :-) I actually did assume ZFS is indeed backwards compatible, but I could not import the pools on the 8.x system, so I asked just to double-check. It seems however I can not import them on the original 7.2 system either, so the pools themselves are the root of the problem, not the new system. BTW: on the original 7.2 system: ZFS filesystem version 6, ZFS storage pool version 6 (just for completeness sake) – ssc Aug 3 '11 at 8:20

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