SSD swaps are reasonably simple, SSD speed is slightly more complex, it depends on what you are running in docker/VM along with the cache pool element. Some of us have split pools as mechanical drives are much more suited to heavy data dumping than NAND (endurance/space), but for docker/VM use, an SSD is much more useful. In time where multiple data pools are a thing, that’s when it’s going to get really fun. Don’t forget you can dedicate individual drives to something via the unassigned devices plugin if you wanted to give a VM total control over a drive.