With persistence storage solved, the remaining core components left are the controllers and NVRAM. AWS offers almost 400 types of EC2 compute instances. Selecting a compute type for the controllers was not a simple task. Pure developers carefully analyzed each type to strike a perfect balance between CPU, memory, network throughput, Instance Store capacity, performance, cost, stability, region/zone availability, etc. The current supported EC2 instance used for the CBS controllers today are the c5n.9xlarge and c5n.18xlarge. However, that could change over time as developers are constantly evaluating new instances and resources released by AWS. For example, the Everpure Cloud Dedicated V20A-R1 models initially leveraged i3 instances for the VDrives. However, starting with the release of PSC Dedicated version 6.1+, VDrives for the V20A-R1 will run on i3en instances, which provide better performance at a lower cost.