Round-trip times to global catalog server are taking more than 10 ms
[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: 2006-03-16
The Microsoft® Exchange Server Analyzer Tool queries the WIN32_PingStatus Microsoft Windows® Management Instrumentation (WMI) class in the root\cimv2 namespace to determine the value for the ResponseTime key. If the Exchange Server Analyzer finds the value for the ResponseTime key to be greater than 10 milliseconds (ms) but less than 100 ms, a warning is displayed.
The ResponseTime key represents the time elapsed (in milliseconds) for the response to the Internet Control Message Protocol (ICMP) echo request (ping) packets sent from the Exchange server to the global catalog server. Global catalog servers used by an Exchange Server computer should always have a response time less than or equal to 10 milliseconds. If the response time exceeds 10 milliseconds, there could be performance or connectivity issues.
To correct this warning
Check to ensure that the global catalog server in question is not overloaded. Use the ADTest.exe tool to perform tests against the global catalog server to see if the hardware can handle the anticipated load.
Check the event logs on the Exchange server and the global catalog server to see if any network-related events have been logged that indicate one or more problems.
Use the DCDiag.exe and NetDiag.exe commands on the global catalog server to verify correct configuration and health.
Finally, investigate the Active Directory® directory service site design. An Active Directory site is considered to be a network section that has high bandwidth and low latency. If the network is not partitioned according to this specification, consider partitioning the network into more Active Directory sites.
When the Analyzer tool runs the WMI query for the ping test, the default packet size and timeout values are overridden. Instead, the Analyzer uses a 4096 ICMP packet size (in place of the default 32 byte) and a 2000 ms timeout value (in place of the default 1000 ms).
Follow these steps to emulate the Analyzer's ping behavior manually.
To perform the ping test manually
Run the following command in the command line window of the Exchange server:
ping -L 4096 -N 6 <Active Server server name>
The command initiates six ping requests of 4096 bytes each.
For more information about the ADTest.exe tool, see the "Active Directory Performance Testing Tool (ADTest.exe)" Web site (http://go.microsoft.com/fwlink/?LinkId=33758).
For more information about the Win32_PingStatus WMI class, see the MSDN® article, "Win32_PingStatus" (http://go.microsoft.com/fwlink/?linkid=33549).
For more information about Active Directory site design, see "Designing the Site Topology" (http://go.microsoft.com/fwlink/?linkid=33551).