The continued adoption, and accleration of interest, of cloud computing has creating an interesting problem for the large enterprise. Most large enterprises have existing private network and intranets. As parts of the organization begin to adopt public and private clouds, there is a challenge of moving data in and out of these clouds.
Data movement is more challenging for a number of reasons including security and network accessability. For example, you can usually can't walk up to these clouds and load a tape or hard drive. And badwidth is often times more restricted than that between internal networks.
Appliations you have running in your private network may not be able to talk directly to the cloude without going through web services or other new networking schemes.
Then there is the question of cost. When does a business decide it is time to bring back data from the cloud? There is a point where keeping certain data in the cloud could become cost prohibative. While the cost of cloude computing and storage is always going down and newer services popup up all the time (like Amazon Glacier for example), this issue is not going away.
Also for Big Data type computation and data storage, at what point is keeping your data running in an Amazone EMR or stored in S3 beceome prohibatively expensive? All these questions are important for organizations to understand as the adoption of cloud computing and Big Data analytics accelerate. There is no simple answer of ourse, but it is important for organizations to consider these questions with both from an IT and financal perspective.