Abstract
The industry needs a protocol that provides efficient storage operations for both data centers and hyperscale applications. Data centers are willing to pay more for more complex interfaces that provide reliable data response times, while Hyperscalers want the lowest cost and greatest flexibility to optimize their cost/performance ratios. Two paths are under consideration to provide deterministic read latency. One is I/O determinism in which the host controls the timing of reads vs. writes to storage elements specified by the controller. This approach requires complex controller firmware leading to highly capable but possibly more expensive controllers. Data centers find this to be easy to install and manage. The other path is Open Channel (Open Fabrics Alliance) where the controller provides information about the physical characteristics of the storage device (e.g., channel and die layout) and the host determines the physical location that data is stored on the medium. Hyperscalers believe this allows them to program their algorithms for writes and reads more effectively to prevent outlier read latencies, as they control all of the knobs on the device. There is also a perception that these SSDs should be less expensive. This configuration requires more initial effort by systems software and continued re-writing of code to keep up with changing SSD technologies that impact what criteria need to be controlled to provide optimal performance.