I have setup a small cluster running a hosted engine using iSCSI. I tried to add a new iSCSI storage domain but this failed as not all hosts could access the storage server. I fixed this problem but it now does not let me add the new storage domain as it shows "lun is already part of storage domain". The engine does not show any storage domains but if I look in the database it shows up there.

How do I remove this broken storage domain and then re-add it?