This is a Technical Report from NetApp explaining the basics of WAFL,Ontap,Hardware:
Additionaly I'd recommend you to attend a NetApp Training (Ontap Administration) where all of your questions are answered in detail.
As much as one would like to view your constant architectural questions with a positive awe of your curiosity, I think you are going to get neither in-depth technical descriptions (these are technical trade secrets, to some extent) nor long, involved "NetApp for Dummies" type of explanations here. If your interest is genuine, then you will need to do a bit more of your own searching and researching.
The architectures of the different series of NetApps throughout the years have simultaneously used both ECC and NVRAM for different purposes.
Roughly speaking (not necessarily ttechnically precise), there are 3 types of memory:
- general purpose memory (for buffer or cache, etc.), those are ECC protected
- NVRAM (for write operations), battery backed
- If you use Flash Cache (read only), that's the 3rd type. And it is also ECC protected.
Hope that helps,