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Event ID 87 — NLB Connection Tracking and Load Balancing

Applies To: Windows Server 2008 R2

The Network Load Balancing (NLB) driver on the host tracks connections to maintain client/network affinity configured on the NLB cluster. If the driver is not functioning properly, NLB may not be able to track TCP connections or may experience load distribution errors.

 

Event Details

Product: Windows Operating System
ID: 87
Source: Microsoft-Windows-NLB
Version: 6.1
Symbolic Name: MSG_ERROR_LOAD_DISTRIBUTION
Message: NLB cluster [%2]: A load distribution error was detected during convergence. This might result in client traffic not being handled, general traffic errors, or connections being reset. To fix the error, restart the cluster by running the PowerShell cmdlet 'Set-NlbClusterNode -Reload' followed by 'Start-NlbClusterNode'.

Resolve

Restart the NLB cluster

A load distribution error was detected during convergence of the Network Load Balancing (NLB) cluster. This may result in client traffic not being handled, general cluster traffic errors, or connections being reset. Convergence is a process by which hosts exchange messages to determine a new, consistent state of the cluster and to elect the default host. During convergence, a new load distribution is determined for hosts that share the handling of network traffic for specific Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) ports. To resolve the load distribution error, you should restart the NLB cluster.

When you are using nlb.exe, you must be a member of the Administrators group on the host that you are configuring, or you must have been delegated the appropriate authority. If you are configuring a cluster or host by running nlb.exe from a computer that is not part of the cluster, you do not have to be a member of the Administrators group on that computer.

To restart the NLB cluster:

  1. Open an elevated Command Prompt window. Click Start, point to All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.
  2. Type nlb.exe reload,which reloads the NLB driver's current parameters from the registry.
  3. Type nlb.exe start, whichstarts cluster operations on the specified hosts.

Verify

When you are using nlb.exe, you must be a member of the Administrators group on the host that you are configuring, or you must have been delegated the appropriate authority. If you are configuring a cluster or host by running nlb.exe from a computer that is not part of the cluster, you do not have to be a member of the Administrators group on that computer.

To verify that all Network Load Balancing (NLB) hosts are in the converged state:

  1. Open an elevated Command Prompt window. Click Start, point to All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.
  2. Type nlb.exe query, which displays the current cluster state and the list of host priorities for the current hosts of the cluster.
  3. Confirm that all hosts display converged as their current state.

 

 

 

NLB Connection Tracking and Load Balancing

NLB Cluster