DStore: A Fast, Tailless, and Quiescent-Free Object Store for PMEM

The advent of fast, byte-addressable persistent memory (PMEM) has fueled a renaissance in re-evaluating storage system design. Unfortunately, prior work has been unable to provide both consistent and fast performance because they rely on traditional cached or uncached approaches to system design, compromising at least one of the requirements. This paper presents DStore, a fast, tailless, and quiescent-free object store for non-volatile memory. To fulfill all three requirements, we propose a novel two-level approach, called DIPPER, which fully decouples the volatile frontend and persistent backend by leveraging the byte addressability and performance of PMEM. The novelty of our approach is in allowing the frontend and backend to operate independently and in parallel without affecting crash consistency. This not only avoids the need to quiesce the system but also allows for increased concurrency in the frontend through the use of observational equivalency. Using this approach, DStore achieves optimal scalability and low latency without compromising on crash consistency. Evaluation on Intel's Optane DC Persistent Memory Module (DCPMM) demonstrates that DStore can simultaneously provide fast performance, uninterrupted service, and low tail latency. Moreover, DStore can deliver up to 6x lower tail latency service level objectives (SLO) and up to 5x higher throughput SLO compared to state-of-the-art PMEM optimized systems.