In the last twenty years we’ve witnessed a steady migration of storage function from the host CPU to the array controller. Storage services including replication, copy services, data migration, data protection and other storage management capabilities have ended up as solutions sold by array vendors and have created a multi-billion dollar industry. It made sense. Lacking a way to store peristent data close to the CPU, on the processor side of the channel, architects chose to use storage networks as the persistent storage alternative of choice. They realized the penalty of performing I/O to external disk was offset by the benefits from sharing persistent storage. Array vendors have also made tremendous strides in performance by using intelligent caching and other sophisticated algorithms and techniques to speed response times and throughput. External storage networks have become the dominant deployment model for the vast majority of mission critical applications.