Performance improvement of block based NAND flash translation layer

Abstract

With growing capacities of flash memories, an efficient layer to manage read and write access to flash is required. NFTL is a widely used block based flash translation layer designed to manage NAND flash memories. NFTL is designed to achieve fast write times at the expense of slower read times. While traditionally, it is assumed that the read traffic to secondary storage is insignificant, as reads are cached, we show that this need not be true for NAND flash based storage due to garbage collection and reclamation processes. In this work, we present two independent techniques that extend NFTL and improve the read throughput in particular. The techniques presented add a minimal amount of RAM overhead to a flash controller, while providing, on an average, a 22.9% improvement in page read times and a 2.6% improvements in page write times on a set of file system and rigorous synthetic benchmarks. The techniques presented are well suited for flash controllers that are typically space constrained and have minimal processing power.

A Temporal Locality-Aware Page-Mapped Flash Translation Layer

“…In addition to these studies on specific FTL design and implementation for improving random write performance, there has been a study on optimizing read throughputs for NAND flash based block devices [27] . Also, there has been a study on efficiently optimizing B-tree data structures over the FTL layer to optimize random write performance [28] , which is independent of FTL optimization research.…”

An endurance-enhanced Flash Translation Layer via reuse for NAND flash memory storage systems

“…In recent years, many studies for FTL schemes (especially hybrid-level FTL schemes) have been proposed [5], [6], [7], [8], [9], [10], [11]. Although the above FTL schemes provide good solutions in terms of endurance, wear-leveling, memory usage, and response time, none of them have considered to reuse free pages in both data blocks and log blocks in a merge operation.…”

Swap-before-hibernate

“…When mounting a flash file system, the whole flash drive should be scanned in order to obtain the meta data of each data block, so the mapping can be re-established [1]. Therefore, to access the flash memory, a conversion interface, such as Flash Translation Layer(FTL) [2][3][4] and NAND Flash Translation Layer [5,6], is needed. Thus, the file system at upper level can view the flash drive as a normal block device, and access it as a hard disk.…”