Automatic Sub-volume level movement??? Non-sensical on NetApp!
"The hints are strong that Data Motion is going to get automated and, hopefully, there will be sub-volume level movement to provide more efficient control of hot data placement, as NetApp's competitors do."
Now that makes no sense whatsoever on a NetApp. If only part of a volume is 'hot', already the second read-access to it would find it in (Flash-)Cache. Writes are always acknowledged to clients as soon as they're safe in NVMEM, so no speeding up necessary there. They're also automatically in Cache, so the next read would already find them there.
98% of use cases are transparently accelerated by Flash-Cache. You can put up to 8TB in a NetApp HA pair...
The other 2% (I know one case) can actually benefit from SSDs. But then it's a *whole* dataset that needs to be fast *all* the time, at the *first* access (because there will probably be no second any time soon) and you wouldn't want the risk of having to warm up the cache after a controller failover. That dataset would go to SSD as a whole, not 'sub-volume'...
I can see lot's of use-cases for automatic DataMotion, but (sub-volume) 'FAST' isn't one of them.
Disclosure: I'm a NCI, a technical Instructor, teaching people (among other things) how to use NetApp controllers. I like their technology, but I'm not an employee...