I have an existing 3220 HA switchless cluster that has been experiencing load issues (controllers staying CPU bound). I'm addressing this by adding an 8040 HA pair (to end up with a 4-node cluster).
However I want the new controllers to "own" the existing shelves/aggregates (1 x SSD shelf in a dedicated stack, 7 x 2246 shelves in a stack, 2 aggregates).
I basically want to unplug the existing SAS Stacks from the old controllers and plug them into the new controllers, and have them detect the existing aggregates and have things just work. (Something tells me that may be a dream).
I will have an additional 2 shelves that I can use for root aggregates/etc for the old 3220 nodes, yes.
Although that's secondary; the thing I'm having a hard time finding information on is basically the head swap procedure for C-dot. There are articles for 7-more, and ones for doing C-Dot where you do "volume migration", but that's not what I need (and downtime for the swap isn't a problem).