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Additional Heartbeat Network Needed

[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 https://go.microsoft.com/fwlink/?linkid=34707.]  

Topic Last Modified: 2008-03-13

The Microsoft Exchange Server Analyzer Tool reads the following registry entry to determine the version of the Microsoft Windows operating system that is running on the Exchange Server computer:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\CurrentVersion

A CurrentVersion value of 4.0 indicates the computer is running Microsoft Windows NT Server 4.0. A value of 5.0 indicates the computer is running Windows 2000 Server, a value of 5.2 indicates the computer is running Windows Server 2003, and a value of 6.0 indicates the computer is running Windows Server 2008.

Next, the Exchange Analyzer queries the Active Directory directory service to determine the value of the serialNumber attribute for all objects that have an object class of msExchExchangeServer. If the string value includes Version 5.5, the computer is running Microsoft Exchange Server version 5.5. If the string value includes Version 6.0, the computer is running Exchange 2000 Server. If the string value includes Version 6.5, the computer is running Exchange Server 2003. If the string value includes Version 8.0, the computer is running Exchange Server 2007.

The Exchange Analyzer then queries the Win32_Service Microsoft Windows® Management Instrumentation (WMI) class to determine the value of the Started key for the Cluster service (ClusSvc). A value of True indicates the Cluster service is started and a value of False indicates the Cluster service is not running.

Finally, the Exchange Analyzer reads the following registry entry to determine the defined role for each network identified in the Exchange server cluster:

HKLM\Cluster\Networks\<NetworkInterfaceGUID>\Role

A value of 1 indicates the network resource has been configured as a dedicated private (heartbeat) network. A value of 2 indicates the network resource has been configured as a dedicated public network (client access). A value of 3 indicates the network resource has been configured as a mixed network that allows both heartbeat traffic and client access traffic.

If the Exchange Analyzer finds that the following conditions are true, the Exchange Analyzer displays an error.

  • The computer is running on the Windows Server 2003 operating system as a node in a cluster.

  • The computer is running Exchange Server 2007.

  • Less than two cluster networks are configured for cluster inter-node communication.

This error means that there are currently less than two cluster networks configured to support cluster heartbeat communication between nodes. As a best practice, we recommend that at least two of the cluster networks be configured to support cluster heartbeat communication.

Because communication between server cluster nodes is critical for smooth cluster operations, two or more independent networks should connect the nodes of a cluster to avoid a single point of failure. It is typical to use two local area networks (LANs). Each cluster network used should fail independently of all other cluster networks. This also means that two cluster networks should not share a common component that could cause both to fail simultaneously.

Recommended network configurations for cluster heartbeat are as follows:

  • At least two private networks used for cluster heartbeat communication.

  • At least one mixed network and one private network used for cluster heartbeat communication.

For specific guidance about how to configure at least two cluster networks for cluster heartbeat communication, see Microsoft Knowledge Base article 258570, "Recommended private "Heartbeat" configuration on a cluster server" (https://go.microsoft.com/fwlink/?linkid=3052&kbid=258750).