So part of what I have been working on has been touching on 2 fairly popular "infrastructure clouds" Amazon EC2 and Rackspace CloudServers. Infrastructure as a service == IaaS == servers on demand (via some api, with illusion of infinite numbers of these resources available - lots more written elsewhere on the web so I won't repeat). I pronounce IaaS "yass" but a good friend of mine says "I Ass" which I may adapt, except in polite company.
In any case, there is a bit of a misunderstanding as to what "ephemeral" means for these virtual cloud machines: with amazons "instance storage" - people still seem to think that if you restart, you lose your storage, heck you even loose your ip. But this is NOT the case ! The only time you lose that storage is if the machine dies in some catastrophic way - or you terminate it. Restarting is just fine. In this sense Rackspace and EC2 are very similar (Rackspace has a higher QoS on their instance stores which is at least equaled by using an EBS store on ec2).
I am surprised that this confusion lives on, but reading the above paragraph for jargon its probably not surprising why. As always experience cures all this.
