Current HPC storage tiering architectures are all about managing costs rather than optimizing overall performance. We will explore a new single-tier architecture from Panasas with the same total SSD and HDD capacities as a typical tiered environment but that, by some measures, results in a 6x better price to performance ratio. The building blocks are the same but the architecture results in better performance.
Here’s an example of some insights from the work. Assume a 10PB effective capacity cold tier using triple replication that is made up of 3000 HDDs of 10TB each. Each HDD can deliver over 150MB/s when doing sequential transfers. That cold tier hardware can deliver half a TB per second, if used effectively. The challenges are that cold tier HDDs are not directly accessible to the application, and conventional wisdom offers no way of ensuring they see only large sequential transfers. This work describes how those issues can be overcome.