Extending SSD Lifetime with Persistent In-memory Metadata Management

Flash-based solid state drive (SSD) is now widely deployed to speed up data intensive applications. However, I/O amplifications caused by file system metadata and journaling shorten the lifetime of SSD. In this paper, a mechanism named Persistent In-memory Metadata Management (referred to as PIMM) is proposed to reduce I/O traffics to SSD by exploiting the persistency and byte-addressability of Non-volatile Memory (NVM). The PIMM decouples data and metadata access paths, putting data on SSD and metadata in NVM at runtime. Thus, metadata is accessed in byte-addressable manner via the memory bus and metadata I/O is eliminated because metadata in NVM is not flushed back to SSD anymore. The PIMM is prototyped on real NVDIMM platform. Extensive evaluations on implemented prototype show that the proposed PIMM reduces the block erase for SSD by up to 91% and improves performance for different workloads.