Minflash: A Minimalistic Clustered Flash Array

NAND flash is seeing increasing adoption in the data center because of its orders of magnitude lower latency and higher bandwidth compared to hard disks. However, flash performance is often degraded by (i) inefficient storage I/O stack that hides flash characteristics under Flash Translation Layer (FTL), and (ii) long latency network protocols for distributed storage.In this paper, we propose a minimalistic clustered flash array (minFlash). First, minFlash exposes a simple, stable, error-free, shared-memory flash interface that enables the host to perform cross-layer flash management optimizations in file systems, databases and other user applications. Second, minFlash uses a controller-to-controller network to connect multiple flash drives with very little overhead. We envision minFlash to be used within a rack cluster of servers to provide fast scalable distributed flash storage. We show through benchmarks that minFlash can access both local and remote flash devices with negligible latency overhead, and it can expose near theoretical max performance of the NAND chips in a distributed setting.