cDOT -> Clustered Data ONTAPcan run in a "single" node
can run in a two-node
can run in an even numbered nodes (up to 24, provided it is an approved config)
cDOT is an expandable OS that is the future of ONTAP.
If you look at 8.3, there is *NO* 7-mode release at all.
All new developments are on Clustered mode.
It also gives you a single, Global Namespace.
In 7-mode, you essentially would manage (from a protocol perspective) two nodes.
cDOT allows control for protocol to/from all nodes simultaneously.