A STUDY ON LINUX KERNEL MODIFICATION FOR PERFORMANCE IMPROVEMENT OF SSD WEAR-OUT-AWARE SYSTEM

Abstract

This study aims to improve the solid-state drive (SSD) wear-out-aware system by modifying the virtual file system (VFS) layer of the Linux kernel. Recently, according to the usage of big data and the development of artificial intelligence, the public can access it from a general PC rather than a research center. They installed several large-capacity SSDs required for learning individually or in a redundant array of inexpensive disks (RAID) 0 format on a PC to store the desired large amount of data. When multiple SSDs are connected and used, if one SSD suffers from wear-out, the input/output performance of other SSDs is adjusted to the corresponding device. Therefore, it is essential to ensure that wear out occurs evenly across multiple SSDs to prevent performance deterioration of the entire system. In this paper, we propose a method of distributing I/O to each SSD by modifying VFS layer of the Linux kernel to improve performance when the SSDs with the same performance but different performance due to wear-out. In other words, VFS was changed to detect each SSD wear out and distribute I/O to SSDs according to the performance ratio in a user-transparent way. Through the experimental results, when using the modified Linux kernel proposed in the paper, we found that the performance improved by 52% in the read and write functions compared to the original Linux kernel. Additionally, compared to RAID 0, it was found that there was a performance improvement of 26% in the read function and 16.7% in the write function. Keywords: Linux Kernel, Solid-State Drive, Redundant Array of Inexpensive Disks, Virtual File System DOI： https://doi.org/10.35741/issn.0258-2724.58.1.40