First and foremost, you should never store anything of lasting value on ephemeral storage in Amazon EC2, except if you know exactly what you are doing and are prepared to always have point in time backups etc. - your question seems to indicate that you might be mistaken about the concept of ephemeral storage, the respective difference between Amazon EC2 Instance Storage an Amazon EBS and the significant implications regarding data safety and backup requirements:
Ephemeral storage will be lost on stop/start cycles and can generally go away, so you definitely don't want to put anything of lasting value there, i.e. only put temporary data there you can afford to lose or rebuild easily, like a swap file or strictly temporary data in use during computations. Of course you might store huge indexes there for example, but must be prepared to rebuild these after the storage has been cleared for whatever reason (instance reboot, hardware failure, ...).
- That's one of the many reasons Eric Hammond excellently summarized in You Should Use EBS Boot Instances on Amazon EC2), which outlines the history of and differences between the two storage concepts and assesses the few remaining possible benefits of ephemeral storage (mainly being plentiful and free).
Problem/Solution
These explanations should clarify why you are unable to backup the ephemeral storage volumes with a mechanism that solely applies to EBS volumes (i.e. EBS snapshots). Accordingly, you can backup the former via regular operating system level backup tool of your choice, with Duplicity being a popular choice optionally facilitating Amazon S3 for example, as addressed in my answer to Easiest to use backup software for live linux server.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
