ZFS unable to import pool

[Tom Evans]

On Wed, Apr 23, 2014 at 1:00 PM, Hugo Lombard <hal at elizium.za.net> wrote:
> [1] Trying to add a single device resulted in zpool add complaining
> with:
>
>   mismatched replication level: pool uses raidz and new vdev is disk
>
> and trying it with three disks said:
>
>   mismatched replication level: pool uses 5-way raidz and new vdev uses 3-way raidz
>
>
> [2] http://lists.freebsd.org/pipermail/freebsd-fs/2014-April/019340.html
>

In earlier versions of ZFS, ISTR that this check did not exist, and
you could do exactly this - expand a pool by adding a vdev that is not
of the same "class" as the existing vdevs on the pool.

If the vdev still existed, this could be fixed by a dumping the data
somewhere, re-creating the pool with the correct vdevs, and restoring
the data.

Otherwise, I think the only solution is to restore from backup.
Perhaps you could roll back the txg before the vdev was added, that is
way above my level of knowledge.

Cheers

Tom