Hexa-SSD: Overcoming capacitance constraints in SSDs

Abstract

This paper presents Hexa-SSD, a novel SSD-internal DRAM management scheme that allows the SSD capacity to scale beyond the slow growth of capacitors. Hexa-SSD judiciously manages the dirty memory footprint within the SSD-internal buffer by using a low-overhead data reordering scheme on the deep queues available in today's storage interfaces. In doing so, our design guarantees crash consistency while using a fraction of the capacitors compared to the state-of-the-art designs. We implement our design in FEMU and demonstrate that Hexa-SSD delivers up to 1.4× higher IOPS and up to 49% less write amplification compared to the existing scheme under power constraints.