SQLIO is a generic tool for testing your disk subsystem. It allows you to specify whether to test random/sequential, data block sizes, queue depth, threading, etc. Despite its name, SQLIO is not part of SQL Server, yet it can be an invaluable tool for determining whether the disk drives slated to support SQL Server can meet the system’s I/O needs.

The tool lets you push the limits of your disk subsystem in order to determine the hardware’s I/O capacity and to identify performance-related issues before deploying SQL Server.

You can use the tool to test a variety of I/O types and sizes against various disk subsystems, including direct attached storage, network attached storage, and storage area networks.