NVMMDS—Metadata Management Method Based on Non-Volatile Memory

Metadata management methods are important factors to affect the performance of file system. A novel metadata management method based on non-volatile memory (NVMMDS) is designed to concern the efficiency and adaptability of current metadata management methods. The structure of NVMMDS and metadata management flow are presented according to the metadata accessing characteristic and management demands. The metadata is stored in non-volatile memory and DRAM is used to cache the update metadata, which provides the foundation for improving performance, avoiding metadata loss and enhancing the metadata operation atomicity. A metadata lookup algorithm based on NVBB-tree is used to uniformly search the metadata in non-volatile memory and metadata cache in DRAM with low overhead. A metadata cache algorithm based on active writing back is used to extend the life of non-volatile memory and avoid the loss of metadata. Compared with the current metadata management methods, our algorithms greatly improve the efficiency and adaptability of metadata management, and avoid the loss of metadata. The NVMMDS prototype is realized on ReiserFs and pNFS. The FileBench and several standard data sets are used to evaluate. The experimental results show that NVMMDS can improve maximum 35% IOPS and I/O performance of file system.