Abstract: Methods and apparatus involve migrating workloads and disaster recovery. A snapshot is taken of a source volume using a volume shadow service. Depending whether a user seeks a migration or disaster recovery action, blocks of data read from the snapshot are transferred to a target volume in various amounts. The amounts of transfer include all of the blocks, only changed blocks between the volumes, or only blocks incrementally changed since a last transfer operation. Users make indications for transfer on a computing device storing and consuming data on the volumes and optionally do so in the context of Novell's Platespin® products. Other features contemplate kernel drivers to monitor the blocks of the volumes, as well as techniques for comparing them. Still other features involve computing systems, volume devices, such as readers, writers and filters, and computer program products, to name a few.