I have a number of AWS EC2 instances which are serving as the backend of a production app. Many of them predate the availability of general SSD storage; however, some of the more recent ones do use SSD for their root volume.
I'd like to convert all the ones that still use magnetic storage to take advantage of SSD storage as well, but I'd prefer not to destroy and recreate any instances which are already on SSDs. How can I determine the type of the storage associated with a particular instance's root volume?