Applies to FAS / AFF ONTAP 9 Answer Check if the resulting shelf is compatible with the existing storage systems When using mixed IOM6 and IOM12 modules in extended shelves, you cannot switch between ...Applies to FAS / AFF ONTAP 9 Answer Check if the resulting shelf is compatible with the existing storage systems When using mixed IOM6 and IOM12 modules in extended shelves, you cannot switch between IOM6 and IOM12 shelves more than once within the same stack Additional Information Convert an original node to a drive shelf (netapp.com) Can I add an IOM6 at the end of a mixed stack of IOM6 and IOM12? - NetApp Knowledge Base Hot-add IOM12/IOM12B shelves to a stack of IOM6 shelves (netapp.com)