Check Disk I/O Subsystem for I/O Delay Problems
This rule checks the event log for error message 833. This message indicates that SQL Server has issued a read or write request from disk, and that the request has taken longer than 15 seconds to return. This error is reported by SQL Server and indicates a problem with the disk I/O subsystem. Delays this long can severely damage the performance of your SQL Server environment.
Best Practices Recommendations
Troubleshoot this error by examining the system event log for hardware-related error messages. Also, examine hardware-specific logs if they are available.
Use Performance Monitor to examine the following counters:
Average Disk Sec/Transfer
Average Disk Queue Length
Current Disk Queue Length
For example, the Average Disk Sec/Transfer time on a computer that is running SQL Server is typically less than 15 milliseconds. If the Average Disk Sec/Transfer value increases, this indicates that the disk I/O subsystem is not optimally keeping up with the I/O demand.