A DRAM-flash index for native flash file systems

Index structures are widely used in file systems and database applications for efficient data management. This paper exploits the respective characteristics of DRAM and flash memory for tree index designs, for which a native file system is taken as an example target in the research. Different from DRAM caching or buffering of flash-memory access in the past work, a hybrid index design that resides over DRAM and flash memory simulaneously is proposed to improve system performance and space management. Tree nodes migrate between DRAM and flash memory, as needed, in response to user access pattern so as to optimize the performance and to reduce managing overhead. The capability of the proposed design is evaluated by a series of experiments, for which we have very encouraging results.