Understanding how Linux kernel IO subsystem works is a key to analysis of a wide variety of issues occurring when running a Linux system. This talk is aimed at helping Linux users understand what is going on and how to get more insight into what is happening.
First we present an overview of Linux kernel block layer including different IO schedulers. We also talk about a new block multiqueue implementation that gets used for more and more devices.
After surveying the basic architecture we will be prepared to talk about tools to peek into it. We start with lightweight monitoring like iostat and continue with more heavy blktrace and variety of tools that are based on it. We demonstrate use of the tools on analysis of real world issues.
Jan Kara, SUSE