The lun clone command does not work across controllers (or even across volumes for that matter). You can ndmpcopy it, but be sure you are copying a consistent LUN in a snapshot or a LUN that is not mounted by a ahost the time. Expect the copy of the LUN on the other side to not be online. You may need to remap it and put it online.
Re: Copying a LUN between nodes in a clustered filer