| title | Check disk IO subsystem for IO delay problems | |
|---|---|---|
| description | Learn how to enable a policy to check the disk IO subsystem for IO delay problems by checking the event log for error message 833 for Policy-Based Management with SQL Server. | |
| author | VanMSFT | |
| ms.author | vanto | |
| ms.date | 12/15/2023 | |
| ms.service | sql | |
| ms.subservice | security | |
| ms.topic | reference | |
| helpviewer_keywords |
|
[!INCLUDE SQL Server] This rule checks the event log for error message 833. This message indicates that [!INCLUDEssNoVersion] 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 [!INCLUDEssNoVersion] and indicates a problem with the disk I/O subsystem. Delays this long can severely damage the performance of your [!INCLUDEssNoVersion] environment.
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 [!INCLUDEssNoVersion] 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.