The limit on the CS200/CS400 platforms is still 3 shelves of capacity, and 1 All Flash Shelf to increase cache - therefore in your situation you can attach one more capacity shelf. You can add a H90T for the third shelf if you wish. You can also scale-up the controllers to the newer gen platforms (they support 6 capacity shelves + 1 AFS) or you can scale out in a Flash Fabric should you wish too.
Happy New Year!
I know originally the CS400 series could only support 3 expansion shelves, but with later updates we were able to do more like having an All-Flash Shelf. With these updates, was the number of shelves increased? I am wondering since I have 2 H65s and an AFS, and need more capacity.
Thank you all and Happy New Year!