Described is a method and system for transparently migrating data between storage systems of a computing environment without disrupting realtime access to the stored data of the storage systems. Specifically, when adding a new storage system to the computing environment, realtime data write operations can be redirected to the new storage system instead of an existing storage system. During the redirection, the data stored on the existing storage system can be accessed for data operations. Concurrently, during the redirection, data stored on the existing storage system can be migrated to the new storage system. When the data migration completes and all the data, stored on the existing storage system prior to the redirection, resides on the new storage system, the new storage system can function as the primary storage system. Thus, storage capacity can increase or be replaced without disrupting data operations.