"Please note that the '128-bitness' of ZFS currently only comes into play
in the on-disk format, and the allowed size of the storage pool. This
should be very easy to maintain compatability with. However, each
filesystem is currently limited to 64-bits, due largely to the lack of
128-bit support in the POSIX interfaces. So there's very little 128-bit
code floating around except at the SPA layer, and as long as you have an
unsigned 64-bit type there shouldn't be any problems at higher layers."
Eric Schrock, Solaris Kernel Development

inymi slovami, aj (open)solaris ZFS je v reale limitovany na 64bit, kedze momentalne neexistuje 128bit-ovy integer ;)

osobne nevidim dovod, preco by to nemalo byt kompatibilne.