Disk timeout is not set at default
[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at http://go.microsoft.com/fwlink/?linkid=34707.]
Topic Last Modified: 2005-11-18
The Microsoft® Exchange Server Analyzer Tool reads the following registry entry to determine whether the disk time-out value has been changed from the default value:
If the Exchange Server Analyzer finds the TimeOutValue present and configured with any value other than 10, and the server is non-clustered, a non-default configuration message is displayed. If the Exchange Server Analyzer finds the TimeOutValue present and configured with any value other than 20, and the server is clustered, a non-default configuration message is displayed.
Disk time-out is a registry setting that defines the time that Microsoft Windows® will wait for a hard disk to respond to a command. On a non-clustered system, this key is not present and a default value of 10 seconds is used for all disks. On a Windows cluster, this key is present and uses a default value of 20 seconds. If the time-out time is more than the value in this registry setting, Windows will show an error and will stop disk access. Sometimes, this may be set to a greater value if you are running multipath disk-access software. Multipath software lets you connect multiple physical paths (such as fiber) to a single disk drive for redundancy. Multipath software manages the multiple physical connections so that Windows handles only a single handle to the disk.
Installing host bus adapters (HBA) or other storage controllers can cause this key to be created and configured. When you install or reinstall these drivers, the TimeOutValue registry value is overwritten with the value that is required by those drivers. You may have to contact the hardware vendor to determine the correct TimeOutValue registry value for your configuration.
This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore the registry if a problem occurs. For information about how to restore the registry, view the "Restore the Registry" Help topic in Regedit.exe or Regedt32.exe.
To revert to the default configuration
Open a registry editor, such as Regedit.exe or Regedt32.exe.
In the right pane, delete the TimeOutValue entry. Alternatively, double-click the TimeOutValue entry and set it to one of the following values:
On a non-clustered server, set the value to 10.
On a clustered server, set the value to 20.
If your hardware manufacturer recommends a different value for either a clustered or non-clustered system, use the value from your hardware manufacturer instead.
Close the registry editor, and then restart the computer for the change to take effect.
Before you edit the registry, and for information about how to edit the registry, see the Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows Registry" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=256986).
For more information about the TimeOutValue entry on clustered systems, see the Knowledge Base article 818877, "Cluster Servers May Experience Connection Timeouts to Drives After You Install or Upgrade to the Windows Clustering Feature in Windows Server 2003" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=818877).