Subscribing to the Cloud service is the easy part. What happens when you want to exit from a particular Cloud and subscribe to another service or withdraw from the Cloud completely?  What are the difficulties you will face?

It is important to understand that you are entrusting your mission-critical information to a third party when you sign up for a Cloud service.  Your data may be replicated on to a number of geographically dispersed servers across the globe.  So, it cannot be a simple matter of giving the Cloud service a notice of withdrawal or merely ceasing to subscribe to the service. There is the liability of ensuring that the Cloud service deletes all the information you have stored with them the instant you decide to withdraw from the service.

Technically, the withdrawal process raises two issues—portability of data and post exit access to user information.

Most Cloud services use proprietary software to backup your data to the Cloud.  This can create a problem.  Richard Stallman, founder of Free Software Foundation and creator of GNU (OS), points out that the Cloud is a trap. [*] The proprietary systems are designed to lock in the user.  The user may have to download all data as an xml file to a local system, or the user may have to download the data before a specified date (as data will not be transferred, it will be simply deleted with the account by the service) or the user may be allowed to move the data to specified Cloud services that have tie-ups with your original Cloud service. A few service providers may download your data to a removable disk and ship it back to you for a charge.  So, a Cloud-to-Cloud transfer may not be an option at all.

What about post exit access? Will the service provider be able to access your data after you have withdrawn from the service?  It is a possibility that must be given serious thought.  Even if the data is removed completely from the primary server, the service provider may have copies of your data stored on replications servers, mirror servers in hot sites and disaster recovery sites.  The deletion in the primary server may not result in a deletion of data from the secondary servers.  This deletion may have to be done manually or may get deleted from these servers over time as new versions of the primary server data replace older versions of the data and older versions are removed completely from the server.

Of course, the process of withdrawal can result in considerable amount of downtime if the organization has been using the Cloud databases as the primary source of information.

Behold! There is a secret weapon to protect you from all these troubles! It is called Service Level Agreements (SLAs). Ensure that you specify all details in the SLAs before you sign up on the dotted lines.

Link: [*] – www.theguardian.com/technology/2008/sep/29/cloud.computing.richard.stallman