Security concerns in Cloud computing II

Continuing with few more concerns as per a Gartner report:

4) Data in the cloud is typically in a shared environment alongside data from other customers. Encryption is effective but isn't a cure-all. "Find out what is done to segregate data at rest," Gartner advises. The cloud provider should provide evidence that encryption schemes were designed and tested by experienced specialists. Encryption accidents can make data totally unusable, and even normal encryption can complicate availability

5) Even if you don't know where your data is, a cloud provider should tell you what will happen to your data and service in case of a disaster. Any offering that does not replicate the data and application infrastructure across multiple sites is vulnerable to a total failure

6) You must be sure your data will remain available even after an event in which the provider goes bankrupt. Ask potential providers how you would get your data back and if it would be in a format that you could import into a replacement application.