From an OpenStack perspective, there are distinct differences between a backup and a snapshot of an instance. Those differences could influence the use of each of those functions. Note that keeping with true cloud behavior, all cloud resources are meant to be disposable. You may ask, what does that statement really mean? It simply means that any instance or volume (resource) created to support your application function should be able to be recreated in some sort of automated fashion. Instilling the pets versus cattle analogy. It is no longer the days of attempting to bring a sick VM back to life; the need of the hour is to destroy the instance, recreate it and off you go again. These principles remove the want for instance backups. With that said, there will be cases when you may want to have a backup of an instance. So, let's first examine the capability of taking an instance backup.
The OpenStack compute service (Nova) functionality of backing up an instance...