TxCache: Transactional cache using byte-addressable non-volatile memories in SSDs

Transaction is a common technique to ensure system consistency but incurs high overhead. Recent flash memory techniques enable efficient embedded transaction support inside solid state drives (SSDs). In this paper, we propose a new embedded transaction mechanism, TxCache, for SSDs with non-volatile disk cache. TxCache revises cache management of disk cache to support transactions using two techniques. First, it persists new-version data in non-volatile disk cache in a shadow way while protecting old-version data from being overwritten. Second, it uses pointers and flags leveraging the byte-addressability to cluster pages of each transaction and manage transaction status. The non-volatility and byte-addressability properties make TxCache an efficient transaction design. Experiments using file system and database workloads show performance improvement up to 46.0% and lifetime extension up to 33.8% compared to a recent transactional SSD design.