SQLIOSIM – To check the IO (SAN/DISK) performance of SQL Server’s disks

A very important factor is to check the IO performance of the disks of your SQL Server. Poor performance of IO can seriously impact your server’s performance and in-turn slows down all associated applications etc. However such situation looks like SQL Server is slow and you can not fix the performance irrespective the amount of effort you spend to configure your server or tune your code. Hence it is always recommended to run an in-depth test on your new server (actually disk) before you commission it to regular use.

SQLIOSIM is a free tool from Microsoft which tests the IO performance of underlying disk systems by simulating a stress test simulation load similar to production database environment. The output is in simple .xml format which captures many important parameters of the disks performance. By analyzing this output, you should be able to decide about the performance of your disks before you commission a server in production. More about this tool including download link may be found at http://support.microsoft.com/kb/231619

However if your server is already in use (specifically if it is a busy or production server) and you need to gauge the performance of IO, I do not recommend using this tool. You can gather the value of all important parameters from various other technologies (like perfmon, dmv etc) with out grinding the server with a simulated load.