Client-side Straggler-Aware I/O Scheduler for Object-based Parallel File Systems

TL;DR

This paper proposes a client-side, log-assisted I/O scheduler for object-based parallel file systems that effectively mitigates storage server stragglers, improving performance in high-performance computing environments.

Contribution

It introduces a novel client-side, log-assisted, straggler-aware I/O scheduler architecture with three algorithms, validated through simulation results.

Findings

Effective mitigation of storage server stragglers

Improved I/O performance in simulations

Validation of scheduler algorithms' efficiency

Abstract

Object-based parallel file systems have emerged as promising storage solutions for high-performance computing (HPC) systems. Despite the fact that object storage provides a flexible interface, scheduling highly concurrent I/O requests that access a large number of objects still remains as a challenging problem, especially in the case when stragglers (storage servers that are significantly slower than others) exist in the system. An efficient I/O scheduler needs to avoid possible stragglers to achieve low latency and high throughput. In this paper, we introduce a log-assisted straggler-aware I/O scheduling to mitigate the impact of storage server stragglers. The contribution of this study is threefold. First, we introduce a client-side, log-assisted, straggler-aware I/O scheduler architecture to tackle the storage straggler issue in HPC systems. Second, we present three scheduling algorithms that can make efficient decision for scheduling I/Os while avoiding stragglers based on such an architecture. Third, we evaluate the proposed I/O scheduler using simulations, and the simulation results have confirmed the promise of the newly introduced straggler-aware I/O scheduler.