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Troubleshooting VMware High Availability (HA) issues in VMware vCenter Server 5.x and 6.0 (2004429)

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  • After upgrading to VMware vCenter Server 5.x and 6.0, VMware High Availability (HA) is no longer working.
  • A red exclamation mark displays on the Cluster Object.
  • Enabling VMware HA fails.
  • Error: Operation Timed out


This article discusses troubleshooting a component of HA (FDM) in vCenter Server 5.x and 6.0.

For information about troubleshooting HA (AAM) in vCenter Server 4.x, see Troubleshooting VMware High Availability (HA) in VMware vSphere 4.x (1001596).


Because vCenter Server 5.x and 6.0 uses Fault Domain Manager (FDM) agents for High Availability (HA), rather than Automated Availability Manager (AAM) agents, the troubleshooting process has changed.

There are other architectural and feature differences that affect the troubleshooting process:
  • There is one main log file (/ var/log/ fdm.log) and syslog integration
  • Datastore Heartbeat
  • Reduced Cluster configuration (approximately 1 minute, as opposed to 1 minute per host)
  • FDM does not require that DNS be configured on the hosts, nor does FDM rely on other Layer 3 to 7 network services. For more information, see How vSphere HA works in the vSphere Availability Guide.

For more information about HA in vCenter Server 5.x, see Comparing VMware HA 4.x and vSphere HA 5.x (2004401).

Known Issues

Common Misconfiguration Issues


  • FDM configuration can fail if ESX hosts are connected to switches with automatic anti-DOS features.

  • FDM does support Jumbo Frames, but the MTU setting has to be consistent from end to end on every device.

  • Some firewall devices block ICMP pings that have an ID of zero. In such cases, FDM could report that some or all slave hosts cannot ping each other, and/or that the isolation addresses cannot be reached. This issue has been resolved in: 

FDM troubleshooting steps

Troubleshooting issues with FDM:

  1. Check the  for known issues. Ensure that you are you using the latest version of vSphere. For information on known issues, see vSphere Release Notes.
  2. Ensure that you have properly configured HA. For information, see How vSphere HA works section of the vSphere Availability Guide.
  3. Verify that network connectivity exists from the vCenter Server to the ESXi host. For more information, see Testing network connectivity with the ping command (1003486).
  4. Verify that the ESXi Host is properly connected to vCenter Server. For more information, see Changing an ESXi or ESX host's connection status in vCenter Server (1003480).
  5. Verify that the datastore used for HA heartbeats is accessible by all hosts.
  6. Verify that all the configuration files of the FDM agent were pushed successfully from the vCenter Server to your ESXi host:

    • Location: /etc/opt/vmware/fdm
    • File Names: clusterconfig (cluster configuration), compatlist (host compatibility list for virtual machines), hostlist (host membership list), and fdm.cfg.

  7. Increase the verbosity of the FDM logs to get more information about the the cause of the issue. For more information, see Changing the verbosity of the VMware High Availability Management Agent (FDM) logs (2004540).

  8. Search the log files for any error message:

    • /var/log/fdm.log or /var/run/log/fdm* (one log file for FDM operations)
    • /var/log/fdm-installer.log (FDM agent installation log)

  9. Contact FDM's Managed Object Browser (MOB), at https://<hostname>/mobfdm, for more information. The MOB can be used to dump debug information about FDM to /var/log/vmware/fdm/fdmDump.log. It can also provide key information about the status of FDM from the perspective of the local ESX server: a list of protected virtual machines, slaves, events etc. For more information, see Managed Object Browser in the vSphere Web Services SDK Programming Guide.

If the issue persists, file a support request with VMware Support and quote this Knowledge Base article ID (2004429) in the problem description. For more information, see How to file a Support Request in My VMware (2006985).

Additional Information

For additional FDM/HA troubleshooting, see the vSphere Troubleshooting Guide.



See Also

Update History

04/30/2013 - Added vCenter Server 5.1.x to Products

Request a Product Feature

To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.


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