caker wrote:
To clarify, I'm asking about one VPS vs one Cloud server (linux box). IaaS, not PaaS.
Well, then, you're defining "cloud" as a VPS.
"Cloud" is a meaningless feel-good term, like "green" or "next-generation" or "healthy." Without some additional context, "cloud" seems to mean "something you can't kick."
Things that are green: hybrid cars, energy-efficient UPSes, recyclable coffee cups, R-134a, cloth diapers, frogs, staycations, new buildings
Things that are cloud: Linode, Gmail, Dropbox, the Amazon family of brands, FedEx Office, fog, Google App Engine, high-availability shared hosting
See, it's a meaningless term on its own. You cannot ask the difference between VPS and Cloud, as it makes as much sense as asking the difference between Toyota Prius and green. Best you can do is come up with reasons why VPS might not be cloud.
Some might say VPS is not cloud because it is typically unmanaged: you have to actually do something to make your application run. To this I say that Google Docs is not cloud because you have to set up formulas and all that to make a spreadsheet balance your checkbook.
Some might say VPS is not cloud because it does not automatically scale. Indeed, this is very closely related to the unmanaged nature of the service. It cannot automatically scale unless you make it automatically scale, which is entirely possible to do.
There are probably other reasons and whatnot, but I think I'm procrastinating by writing this post, so I shall stoke the fire and be off.