A Case for Heterogeneous Flash in the Datacenter

We explore the idea of heterogeneous NAND flash which possesses pages and blocks of multiple sizes. This heterogeneity can then be exploited to accommodate the diversity in data access patterns found in most datacenter storage workloads. We identify various tradeoffs offered by such pages and blocks. By characterizing seven real-world I/O traces, we identify metrics that have a bearing on the efficacy as well as design of such a heterogeneous flash. We use the observations of our workload characterization to discuss the pros and cons of different implementation styles, management schemes and implications for datacenters.