USENIX ATC '22

Currently Playing: USENIX ATC '22 - StRAID: Stripe-threaded Architecture for Parity-based RAIDs with Ultra-fast SSDs

USENIX ATC '22 - StRAID: Stripe-threaded Architecture for Parity-based RAIDs with Ultra-fast SSDs Shucheng Wang, Qiang Cao, and Ziyi Lu, Wuhan National Laboratory for Optoelectronics, HUST; Hong Jiang, Department of Computer Science and Engineering, UT Arlington; Jie Yao, School of Computer Science and Technology, HUST; Yuanyuan Dong, Alibaba Group Popular software storage architecture Linux Multiple-Disk (MD) for parity-based RAID (e.g., RAID5 and RAID6) assigns one or more centralized worker threads to efficiently process all user requests based on multi-stage asynchronous control and global data structures, successfully exploiting characteristics of slow devices, e.g., Hard Disk Drives (HDDs). However, we observe that, with high-performance NVMe-based Solid State Drives (SSDs), even the recently added multi-worker processing mode in MD achieves only limited performance gain because of the severe lock contentions under intensive write workloads. In this paper, we propose a novel stripe-threaded RAID architecture, StRAID, assigning a dedicated worker thread for each stripe-write (one-for-one model) to sufficiently exploit high parallelism inherent among RAID stripes, multi-core processors, and SSDs. For the notoriously performance-punishing partial-stripe writes, StRAID presents a two-phase stripe write mechanism to opportunistically aggregate stripe-associated writes to minimize write I/Os; and designs a parity cache to reduce write-induced read I/Os on parity disks. We evaluate a StRAID prototype with a variety of benchmarks and real-world traces. StRAID is demonstrated to consistently outperform MD by up to 5.8 times in write throughput without affecting the read performance. View the full USENIX ATC '22 program at https://www.usenix.org/conference/atc22/technical-sessions