The architecture of eNVy, a non-volatile, main memory storage system
Master of Science
This paper describes the architecture of eNVy, a large non-volatile main memory storage system built primarily with Flash memory. Flash provides persistent storage with solid-state memory access times at a lower cost than other solid-state technologies. eNVy presents its storage space as a linear, memory mapped array rather than as a disk emulator in order to provide an efficient and easy to use software interface. Flash chips are write-once, bulk-erase devices whose contents cannot be updated in-place. They suffer from slow write times and limited program/erase cycles. eNVy uses a copy-on-write scheme, some battery-backed SRAM, and parallel operation to overcome these problems and provide low latency in-place update semantics. A specialized cleaning algorithm maximizes the lifetime of the Flash array. Simulations show that eNVy can handle I/O rates corresponding to approximately 30,000 TPS on the TPC-A benchmark with average latencies as low as 180ns for reads and 200ns for writes.
Electronics; Electrical engineering; Computer science