FreeNas 7 to 8 and zpool?

[McZ]

I have been running FreeNAS 0.7.2 for a while and I want to upgrade. And I know the new FreeNAS doesn't support the old configuration and I don't care. What I do care about is my zpool I have been reading I can't go back to 0.7.2 because it use an older zfs version.

So my question is will zfs import auto upgrade my zfs pool to the current zfs version of the OS running?
or will it keep the version it was created with (the old freenas version) and an upgrade of the zpool must be done manually?

if it is the manual way, what happens with stuff (zfs create zpool1/***) created with the new version?

Why I'm asking is because I run FreeNAS from USB and it would be rather painless to prepare a second USB with FreeNAS 8 on and just shutdown my NAS and swap USB. The problem would be if ZFS import auto upgrade my zpool, then I can't go back, and that would destroy the posibility to go back to my old working freenas.

 

[ProtoSD]

It won't upgrade your pool(s) automatically, but new pools created like your example will be the newer ZFS v15 that's in FreeNAS8. I believe there shouldn't be any problems with doing your musical USB swap.

 

[louisk]

The new FreeNAS (8.x) should be able to import the old zpool w/o any issues (I haven't tried this for about 6mo, but it worked). At the time, there was no gui way to upgrade anything, so I manually ran the upgrade on the CLI. No problems.

If you want to (potentially) go back to FreeNAS 7, just don't upgrade the pool.