Disk I/O Monitoring: `iostat`, `iotop`

Disk Input/Output (I/O) refers to the data moving between your computer's CPU and its storage devices (like hard drives or SSDs).

Monitoring disk I/O is crucial for understanding system performance. Slow disk I/O can be a major bottleneck, making your applications and overall system feel sluggish, even if your CPU and memory are underutilized.

The iostat command is part of the sysstat package and is used to report CPU statistics and device I/O statistics.

It provides a system-wide view of disk activity, helping you identify if your storage devices are struggling to keep up with demand.

Running iostat without any options gives you a snapshot of current I/O performance.