zfs and 9.1 upgrade

[Graeme Dargie]

Hi All

Upgraded 3 machines today from 9.0 to 9.1 all three run ZFS as a storage but not as a boot file system. One machine out of the three ended up with a very sick looking ZFS pool, not a big deal as this machine is a backup mirror for another system. So I did a zpool destroy tank  then zpool create tank raidz ada1 ada2 ada3 ada4

ZFS tells me that ada1 might be part of an active pool and use -f to override this.

zpool create -f tank raidz ada1 ada2 ada3 ada4
cannot create 'tank': no such pool or dataset

Any clues anyone?

Regards