AutoBahn: a concurrency control framework for non-volatile file buffer

Storage systems in general and databases in particular usually balance between write durability and performance. It is not uncommon that write durability often relies on transaction systems that also offer a relaxed model of durability for performance. As hardware vendors provision more cores and faster storage devices, attaining fast data durability for concurrent file writes is demanding to high-performance storage systems in large-scale cluster systems. We approach the challenge by proposing a system that uses a small amount of fast persistent memory for buffering concurrent file writes while preserving data durability. The main technical issue in designing a durable file buffer is allowing concurrent file writes to store data in a shared and limited space of persistent memory without incurring lock or resource contention. This article addresses such issue and presents AutoBahn, a durable file buffer that expedites file I/O operations. To prove practicality and effectiveness, we implemented a prototype of AutoBahn in Linux-4.8.7 and ran several key-value systems—Redis, RocksDB, and WiredTiger—on AutoBahn. Evaluation results on a multicore server demonstrate that all the key-value systems achieved performance levels almost matching the non-durable counterpart. AutoBahn is a useful method that can efficiently deal with concurrent file I/O streams on multicores and fast storage devices.