Adjust convergence parameters

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

To adjust convergence parameters

  1. Click Start, click Run, and then, in Open, type regedit.

  2. Click the registry key:

    HKEY_LOCAL_MACHINE\System\CurrentControlSet

    \Services\WLBS\Parameters\Interface\Network adapter ID

  3. Edit the AliveMsgPeriod or AliveMsgTolerance parameters as necessary.

  4. Restart the computer.

Caution

  • Incorrectly editing the registry may severely damage your system. Before making changes to the registry, you should back up any valued data on the computer.

Notes

  • To perform this procedure, you must be a member of the Administrators group on the local computer, or you must have been delegated the appropriate authority. If the computer is joined to a domain, members of the Domain Admins group might be able to perform this procedure. As a security best practice, consider using Run as to perform this procedure.

  • The purpose of this procedure is to allow you to control both the message exchange period and the number of missed messages required to initiate convergence. For more information, see Related Topics.

  • The AliveMsgPeriod value holds the message exchange period in milliseconds, and the AliveMsgTolerance value specifies how many exchanged messages from a host can be missed before the cluster initiates convergence.

    These numbers should reflect your installation's requirements. A longer message exchange period reduces the heartbeat traffic needed to maintain fault tolerance, but it increases the time that it takes for Network Load Balancing to stop sending network messages to an offline host. Likewise, increasing the number of message exchanges prior to convergence reduces the number of unnecessary convergence initiations due to network congestion, but it too increases the time for an offline host to stop receiving network traffic.

    Using the default values, 5 seconds are needed to discover a missing host, and another 5 seconds are needed for the cluster to redistribute the load. A total of 10 seconds to stop sending network traffic to an offline host should be acceptable for most TCP/IP applications. This configuration incurs very low networking overhead.

  • WLBS stands for Windows NT Load Balancing Service, the former name of Network Load Balancing in Windows NT 4.0. For reasons of backward compatibility, WLBS continues to be used in certain instances.

Information about functional differences

  • Your server might function differently based on the version and edition of the operating system that is installed, your account permissions, and your menu settings. For more information, see Viewing Help on the Web.

See Also

Concepts

How Network Load Balancing works
Nlbmgr