Old ZFS recovery/upgrade strategy

Question

The motherboard of a ZFS-based NAS died, and I'm now trying to access the data and move it, or revive the NAS. Debian and ZFS haven't been updated since 2015 or so, however. What I can glean from the log-files is:

• ZFS 0.6.4
• ZFS pool version 5000
• ZFS filesystem 5
• Debian Wheezy
• Linux 3.2.0-4

So far so good. This Debian is rather old, though, and ZFS and some dependencies have to be compiled by hand to get it all going again - the apt repos have been largely purged of this old stuff, it seems. So, I'm wondering if it's safe to just spin up a modern Ubuntu, say, and simply create the ZFS pools again. The ZFS should get updated in any case, so it would be really neat if this just worked with Ubuntu 20, for example...

What came up after a bit of digging is that the ZFS pool version today is still 5000 according to Wikipedia. I can't find any information about what this "ZFS filesystem 5" refers to. I'm not sure at all what the right upgrade strategy is, or what the relevant documentation might be. Any pointers would be very welcome.

Answer 1

Here's what I did:

1. Install Ubuntu 20.04, install zfsutils-linux.
2. Run zpool import, this will list all the pools the system can find.
3. Run zpool import -f <poolname> (the -f is required because ZFS will otherwise complain that the "pool was previously in use from another system").