Storage is one of the slowest components in a server's system, but is still the most important component. Storage is mainly used as a persistence mechanism to store a large amount of processed/unprocessed data. A slow storage device generally results in heavy utilization of read write buffers and higher memory consumption. You will see higher CPU usage, but most of the CPU time is spent waiting for I/O requests.
The recent developments of the flash storage medium have vastly improved storage performance. Still, it's one of the slowest performing components and needs proper planning— I/O planning in the application code, plus enough main memory for read write buffers.
In this recipe, we will learn to monitor storage performance. The main focus will be on local storage devices rather than network storage.