A Flash Tier For Tiered Transaction Storage System

Abstract

A tiered transaction storage subsystem (T2) providing both ease of programming and cost effectiveness is proposed. The dissertation explores the system aspects of a tiered storage system consisting of memory and flash tiers and focuses on preserving the simple programming interfaces of the memory tier and designing efficient flash-based subsystems to provide cost effectiveness. To address the ease of programming, T2’s flash-tier subsystem provides memory-compatible interfaces through region abstraction, which creates an illusion of transactional memory out of non-transactional commodity flash storage. To address the effectiveness or high performance, T2 incorporates the higher-level transaction state into the transaction-aware mapping table. T2 exploits Compare-And-Swap (CAS) operations on the transaction state to implement atomic transactional primitives and utilizes an atomic buffer reservation technique to allow concurrent writes on the multiple flush buffers. It also exploits asynchronous I/O operations to increase throughput. The experiment shows that flash tier’s throughput per dollar can be competitive or better than the memory tier in read-oriented workloads. Furthermore, the simple programming model preserved by T2 allows application developers to tackle big data workloads correctly and with agility.