Section: New Results

Data Management in Flash Memory (Axis 1)

Participant : Luc Bouganim [correspondent] .

Understanding Flash I/O Pa erns on Open-Channel Solid-State Drives: Solid-State Drives (SSDs) have gained acceptance by providing the same block device abstraction as magnetic hard drives, at the cost of suboptimal resource utilization and unpredictable performance. Recently, Open-Channel SSDs have emerged as a means to obtain predictably high performance, based on a clean break from the block device abstraction. Open-channel SSDs embed a minimal flash translation layer (FTL) and expose their internals to the host. The Linux open-channel SSD subsystem, LightNVM, lets kernel modules as well as user-space applications control data placement and I/O scheduling. This way, it is the host that is responsible for SSD management. But what kind of performance model should the host rely on to guide the way it manages data placement and I/O scheduling? For addressing this question we have defined uFLIP- OC, a benchmark designed to identify the I/O patterns that are best suited for a given open-channel SSD. Our experiments on a Dragon- Fire Card (DFC) SSD, equipped with the OX controller, illustrate the performance impact of media characteristics and parallelism. In [17], we present uFLIP-OC and how it can be used to guide the design of host-based data systems on open-channel SSDs.