hybridFS: Integrating NAND Flash-Based SSD and HDD for Hybrid File System

摘要

In this paper, we present a hybrid file system, called hybridFS, whose primary objective is to put together attractive features of both HDD and SSD, to construct a large-scale, virtualized address space in a cost-effective way. HybridFS was designed to take advantage of SSD's high I/O performance, while providing a flexible internal structure to utilize excellent sequential performance of existing file systems. To optimize the limited space capacity of SSD partition, hybridFS supports to define several data sections whose extent size can differ from each other. Such a pre-determined extent size enables to define a data section in such a way to minimize the wasted hole of an extent, by closely matching a multiple of extent size to the file size to be allocated in the data section. Several experiments were conducted to verify the performance of hybridFS.