NOHOST : a new storage architecture for distributed storage systems

Abstract

This thesis introduces a new NAND flash-based storage architecture, NOHOST, for distributed storage systems. A conventional flash-based storage system is composed of a number of high-performance x86 Xeon servers, and each server hosts 10 to 30 solid state drives (SSDs) that use NAND flash memory. This setup not only consumes considerable power due to the nature of Xeon processors, but it also occupies a huge physical space compared to small flash drives. By eliminating costly host servers, the suggested architecture uses NOHOST nodes instead, each of which is a low-power embedded system that forms a cluster of distributed key-value store. This is done by refactoring deep I/O layers in the current design so that refactored layers are light-weight enough to run seamlessly on resource constrained environments. The NOHOST node is a full-fledged storage node, composed of a distributed service frontend, key-value store engine, device driver, hardware flash translation layer, flash controller and NAND flash chips. To prove the concept of this idea, a prototype of two NOHOST nodes has been implemented on Xilinx Zynq ZC706 boards and custom flash boards in this work. NOHOST is expected to use half the power and one-third the physical space as compared to a Xeon-based system. NOHOST is expected to support the through of 2.8 GB/s which is comparable to contemporary storage architectures.