In his recent article, Patrick Thibodeau at Computerworld pointed out that the number of datacenters are declining; indeed the total square ft. of raised flooring is also declining. He attributes this to the consolidation of data centers and the renting of server and storage resources from the public cloud. While this is quite true, underlying this is a deeper trend; a trend to a new computer platform architecture. This new architecture is called various things depending on the operating “stack” running on it: Hyper Converged Infrastructure, Software Defined Storage, or Scale-Out. What it all has in common is the utilization of very dense, very cheap servers with direct attached storage (disk or flash).
This is what the public cloud providers are using for compute servers and for storage platforms. This is what is driving the big consolidation projects in large companies. This is the standard platform for Big Data, machine learning, and IoT. It is the target platform for containers and container orchestration systems.
SANs, NAS, and big scale-up servers all take up lots of rackspace and floorspace. As modern workloads replace old ones and are deployed on the new super dense, super cheap platform, floor space requirements go down.
There is a temporary cost advantage of using public cloud resources, running on the new platform, compared to running on-prem with the old platform. As organizations learn to use the new platform, however, the massive “Move to the Cloud” will slow and a balance will be established between what makes sense in the public cloud vs. on-prem.