Design and Implementation of Cache Manager for Hybrid Storage

The technology and cost barrier of the SSD motivatedmany research groups and companies to merge the SSDwith low cost and large capacity storage device, HardDisk Drive (HDD). As the NAND flash memorytechnology is getting more advanced, price of NANDflash memory dropped dramatically. As number of bitsper cell in NAND flash memory is increasing, the priceof $/GByte is reduced. This trend will continue until themarket sought for another media as a stable and faststorage media. NAND flash based Solid State Drive(SSD) is considered as a choice for replacing Hard DiskDrive (HDD) to reduce and minimize the gap betweenIO latency DRAM of a storage device. In this work, wefirst examine three existing cache manager solutionsand study if advertised measurements hold in in-housebenchmark environment. We describe what has to beconsidered in implementing cache managers, and alsodescribe design and implementation of a cache managerand measure its caching performanceThis work is sponsored by IT R&D programMKE/KEIT. [No.10035202, Large Scale hyperMLCSSD Technology Development]