We know that the Linux storage system I/O stack consists of the file system layer, the general block layer, and the device layer.
Among them, the general block layer is the core of Linux disk I/O. Upwards, it provides a standard interface for accessing block devices for file systems and applications; downwards, it abstracts various heterogeneous disk devices into a unified block device and responds to I/O sent by the file system and applications.
In this article, let’s take a look at the performance indicators of the disk and how to observe these indicators.
Linux Disk Performance Metrics
When it comes to measuring disk performance, we often mention five common indicators: utilization, saturation, IOPS, throughput, and response time. These five indicators are the basic indicators to measure disk performance.
- Utilization: The percentage of time the disk is processing I/O. Excessive usage (such as more than 80%) usually means that there is a performance bottleneck in disk I/O.
- Saturation: Refers to how busy the disk is processing I/O. Excessive saturation means that the disk has a serious performance bottleneck. When saturation is 100%, the disk cannot accept new I/O requests.
- IOPS (Input/Output Per Second)…
