iostat
also: io statistics
A system monitoring tool that reports CPU usage and input/output statistics for block devices and partitions, helping identify storage performance issues.
iostat is a command-line utility that displays detailed CPU and disk I/O statistics. It's part of the sysstat package and helps system administrators diagnose performance bottlenecks by showing read/write operations, throughput, and device utilization.
When run without arguments, iostat shows a snapshot of CPU and disk statistics since boot. With options like iostat 2 5, it continuously monitors devices every 2 seconds for 5 iterations, making it useful for real-time performance analysis.
Example output shows metrics such as %user, %iowait (percentage of time CPU waits for I/O), tps (transactions per second), and kB_read/s (kilobytes read per second). High %iowait or low throughput may indicate disk saturation or performance problems.