Achieving Both Performance and Reliability in An Asymmetric File System on Disaggregated Persistent Memory

The ultra-fast persistent memories (PMs) promise a practical solution towards high-performance distributed file systems. This paper examines and reveals a cascade of performance and reliability issues in the current PM provision scheme, which not only underutilizes fast PM devices but also leads to severe consequences, such as throughput degradation, load imbalance, and even service outage. To remedy these, we introduce Ethane+, a rack-scale, distributed file system built on disaggregated persistent memory (DPM). Through resource separation using fast data connection technologies, DPM achieves efficient and cost-effective PM sharing while supporting strong fault isolation. To unleash such hardware potentials, Ethane+ incorporates an asymmetric file system architecture inspired by the imbalanced resource provision feature of DPM. It splits a file system into a control-plane FS and a data-plane FS, and designs these two planes with dual goals of best hardware utilization and hardening file system reliability. Evaluation results demonstrate that Ethane+ reaps the DPM hardware benefits, performs up to 60 × better than modern distributed file systems, resists both software and hardware faults, and improves data-intensive application throughputs by up to 15 ×.