A Novel Persistent In-memory Filesystem for the Fusion of Memory and Storage

Emerging non-volatile memory (NVM) technologies provide opportunities for the fusion of memory and storage. The fusion of memory and storage can exploit NVM's byte-addressability and achieve the large capacity data storage. However existing file systems built for traditional disk-based storage systems will not suit for the system based on fusion of memory and storage, which could not take full advantage of the performance that NVM should provide. Thus, it's necessary to redesign file system, over NVM medium. This paper attempts to achieve the fusion of memory and storage at the software level, which exploits NVM's byte-addressability and achieves the large capacity data storage. We converge the management of main memory and storage by implementing a file system called FRFS which optimized for NVM as the system software layer to manage the NVM medium. The proposed file system integrates the management of main memory and storage, which by adopting file page tables to fuse the memory and storage management. FRFS converges the indexing metadata and address mapping of file data into the persistent file page table. A file can be mapped into virtual address space at a constant time by embedding file page table into the calling process. Since the mapping has been established, applications can read or write the file in-place without page fault interrupt. Moreover, the addressing of file data can be efficiently handled by Memory Management Unit (MMU) hardware instead of traversing software routine, which shorting the file access path. Extensive experiments are performed on the Intel server. The results indicate that FRFS can achieve excellent performance and verify the feasibility about the fusion of memory and storage management.