You might encounter error messages when trying to use VMware Fault Tolerance (FT). The following tables list some of these error messages. For each error message there is a description and information about resolving the error, if applicable. In addition to the vSphere Client Tasks & Events tab, you can also view FT errors in the virtual machine's Summary tab.

The following table lists some of the error messages you can encounter if your host or cluster is not configured appropriately to support FT. See Fault Tolerance Checklist for details about the host and cluster configuration requirements for FT.

Configuration Errors

Error Message

Description and Solution

Host CPU is incompatible with the virtual machine's requirements. Mismatch detected for these features: CPU does not match

FT requires that the hosts for the Primary and Secondary VMs use the same CPU. Enable FT on a virtual machine registered to a host with a matching CPU model, family, and stepping within the cluster. If no such hosts exist, you must add one. This error also occurs when you attempt to migrate a fault tolerant virtual machine to a different host.

The Fault Tolerance configuration of the entity {entityName} has an issue: Fault Tolerance not supported by host hardware

FT is only supported on specific processors and BIOS settings with Hardware Virtualization (HV) enabled. To resolve this issue, use hosts with supported CPU models and BIOS settings.

Virtual Machine ROM is not supported

The virtual machine is running VMI kernel and is paravirtualized. VMI is not supported by FT and should be disabled for the virtual machine.

Host {hostName} has some Fault Tolerance issues for virtual machine {vmName}. Refer to the errors list for details

To troubleshoot this issue, in the vSphere Client select the failed FT operation in either the Recent Tasks pane or the Tasks & Events tab and click the View details link that appears in the Details column.

The Fault Tolerance configuration of the entity {entityName} has an issue: Check host certificates flag not set for vCenter Server

The "check host certificates" box is not checked in the SSL settings for vCenter Server. You must check that box. See Enable Host Certificate Checking.

The Fault Tolerance configuration of the entity {entityName} has an issue: HA is not enabled on the virtual machine

This virtual machine is on a host that is not in a VMware HA cluster or it has had VMware HA disabled. Fault Tolerance requires VMware HA.

The Fault Tolerance configuration of the entity {entityName} has an issue: Host is inactive

You must enable FT on an active host. An inactive host is one that is disconnected, in maintenance mode, or in standby mode.

Fault Tolerance has not been licensed on host {hostName}.

Fault Tolerance is not licenced in all editions of VMware vSphere. Check the edition you are running and upgrade to an edition that includes Fault Tolerance.

The Fault Tolerance configuration of the entity {entityName} has an issue: No vMotion license or no virtual NIC configured for vMotion

Verify that you have correctly configured networking on the host. See Configure Networking for Host Machines. If it is, then you might need to acquire a vMotion license.

The Fault Tolerance configuration of the entity {entityName} has an issue: No virtual NIC configured for Fault Tolerance logging

An FT logging NIC has not been configured. See Configure Networking for Host Machines for instructions.

Host {hostName} does not support virtual machines with Fault Tolerance turned on. This VMware product does not support Fault Tolerance

The product you are using is not compatible with Fault Tolerance. To use the product you must turn Fault Tolerance off. This error message primarily appears when vCenter Server is managing a host with an earlier version of ESX/ESXi or if you are using VMware Server.

The Fault Tolerance configuration of the entity {entityName} has an issue: Fault Tolerance not supported by VMware Server 2.0

Upgrade to VMware ESX or ESXi 4.1 or later.

The build or Fault Tolerance feature version on the destination host is different from the current build or Fault Tolerance feature version: {build}.

FT feature versions must be the same on current and destination hosts. Choose a compatible host or upgrade incompatible hosts.

There are a number of virtual machine configuration issues that can generate error messages.

Two error messages you might see if the virtual machine configuration does not support FT.

The Fault Tolerance configuration of the entity {entityName} has an issue: The virtual machine's current configuration does not support Fault Tolerance

The Fault Tolerance configuration of the entity {entityName} has an issue: Record and replay functionality not supported by the virtual machine

FT only runs on a virtual machine with a single vCPU. You might encounter the following errors when attempting to turn on FT on a multiple vCPU virtual machine:

The virtual machine has {numCpu} virtual CPUs and is not supported for reason: Fault Tolerance

The Fault Tolerance configuration of the entity {entityName} has an issue: Virtual machine with multiple virtual CPUs

There are vSphere features with which FT does not interoperate. If you attempt to turn on FT on a virtual machine using a vSphere feature which FT does not support you might see one of the following error messages. To use FT, you must disable the vSphere feature on the offending virtual machine or enable FT on a virtual machine not using these features.

The Fault Tolerance configuration of the entity {entityName} has an issue: The virtual machine has one or more snapshots

The Fault Tolerance configuration of the entity {entityName} has an issue: Template virtual machine

The following error messages might occur if your virtual machine has an unsupported device. To enable FT on this virtual machine, remove the unsupported device(s), and turn on FT.

The file backing ({backingFilename}) for device Virtual disk is not supported for Fault Tolerance

The file backing ({backingFilename}) for device Virtual Floppy is not supported for Fault Tolerance

The file backing ({backingFilename}) for device Virtual CDROM is not supported for Fault Tolerance

The file backing ({backingFilename}) for device Virtual serial port is not supported for Fault Tolerance

The file backing ({backingFilename}) for device Virtual parallel port is not supported for Fault Tolerance

The following table lists other virtual machine configuration errors. See Fault Tolerance Interoperability for more details.

Other Virtual Machine Configuration Issues

Error Message

Description and Solution

The specified host is not compatible with the Fault Tolerance Secondary VM.

Refer to Troubleshooting Fault Tolerance for possible causes of this error.

No compatible host for the Secondary VM {vm.name}

Refer to Troubleshooting Fault Tolerance for possible causes of this error.

The virtual machine's disk {device} is using the {mode} disk mode which is not supported.

The virtual machine has one or more hard disks configured to use Independent mode. Edit the setting of the virtual machine, select each hard disk and deselect Independent mode. Verify with your System's Administrator that this is acceptable for the environment.

The unused disk blocks of the virtual machine's disks have not been scrubbed on the file system. This is needed to support features like Fault Tolerance

You have attempted to turn on FT on a powered-on virtual machine which has thick formatted disks with the property of being lazy-zeroed. FT cannot be enabled on such a virtual machine while it is powered on. Power off the virtual machine, then turn on FT and power the virtual machine back on. This changes the disk format of the virtual machine when it is powered back on. Turning on FT could take some time to complete if the virtual disk is large.

The disk blocks of the virtual machine's disks have not been fully provisioned on the file system. This is needed to support features like Fault Tolerance

You have attempted to turn on FT on a powered-on virtual machine with thin provisioned disks. FT cannot be enabled on such a virtual machine while it is powered on. Power off the virtual machine, then turn on FT and power the virtual machine back on. This changes the disk format of the virtual machine when it is powered back on. Turning on FT could take some time to complete if the virtual disk is large.

The following table lists error messages you might encounter while using fault tolerant virtual machines.

Operational Errors

Error Message

Description and Solution

No suitable host can be found to place the Fault Tolerance Secondary VM for virtual machine {vmName}

FT requires that the hosts for the Primary and Secondary VMs use the same CPU model or family and have the same FT version number or host build number and patch level. Enable FT on a virtual machine registered to a host with a matching CPU model or family within the cluster. If no such hosts exist, you must add one.

The Fault Tolerance Secondary VM was not powered on because the Fault Tolerance Primary VM could not be powered on.

vCenter Server will report why the primary could not be powered on. Correct the conditions and then retry the operation.

Operation to power On the Fault Tolerance Secondary VM for {vmName} could not be completed within {timeout} seconds

Retry the Secondary VM power on. The timeout can occur because of networking or other transient issues.

vCenter disabled Fault Tolerance on VM {vmName} because the Secondary VM could not be powered on

To diagnose why the Secondary VM could not be powered on, see Troubleshooting Fault Tolerance.

Resynchronizing Primary and Secondary VMs

Fault Tolerance has detected a difference between the Primary and Secondary VMs. This can be caused by transient events which occur due to hardware or software differences between the two hosts. FT has automatically started a new Secondary VM, and no action is required. If you see this message frequently, you should alert support to determine if there is an issue.

The Fault Tolerance configuration of the entity {entityName} has an issue: No configuration information for the virtual machine

vCenter Server has no information about the configuration of the virtual machine. Determine if it is misconfigured. You can try removing the virtual machine from the inventory and re-registering it.

Cannot change the DRS behavior for Fault Tolerance Secondary VM {vmName}.

You cannot change the DRS behavior on FT Secondary VMs. This configuration is inherited from the Primary VM.

Virtual machines in the same Fault Tolerance pair cannot be on the same host

You have attempted to vMotion a Secondary VM to the same host a Primary VM is on. A Primary VM and its Secondary VM cannot reside on the same host. Select a different destination host for the Secondary VM.

Cannot add a host with virtual machines that have Fault Tolerance turned On to a non-HA enabled cluster

FT requires the cluster to be enabled for VMware HA. Edit your cluster settings and turn on VMware HA.

Cannot add a host with virtual machines that have Fault Tolerance turned On as a stand-alone host

Turn off Fault Tolerance before adding the host as a stand-alone host to vCenter Server. To turn off FT, add the host to a VMware HA cluster, right-click each virtual machine on the host and select Turn Off Fault Tolerance. Once FT is disabled, the host can be made into a stand-alone host.

Cannot set the HA restart priority to 'Disabled' for the Fault Tolerance VM {vmName}.

This setting is not allowed for a FT virtual machine. You only see this error if changing the restart priority of an FT virtual machine to Disabled.

Host already has the recommended number of {maxNumFtVms} Fault Tolerance VMs running on it

To power on or migrate more FT virtual machines to this host either move one of the existing Fault Tolerance virtual machines to another host or disable this restriction by setting the VMware HA advanced option das.maxftvmsperhost to 0.

The following table lists error messages you might encounter while using the SDK to perform operations.

SDK Operational Errors

Error Message

Description and Solution

This operation is not supported on a Secondary VM of a Fault Tolerant pair

An unsupported operation was performed directly on the Secondary VM using the API. FT does not allow direct interaction with the Secondary VM (except for relocating or migrating it to a different host).

The Fault Tolerance configuration of the entity {entityName} has an issue: Secondary VM already exists

The Primary VM already has a Secondary VM. Do not attempt to create multiple Secondary VMs for the same Primary VM.

The Secondary VM with instanceUuid '{instanceUuid}' has already been enabled

An attempt was made to enable FT for a virtual machine on which FT was already enabled. Typically, such an operation would come from an API.

The Secondary VM with instanceUuid '{instanceUuid}' has already been disabled

An attempt was made to disable FT for a Secondary VM on which FT was already disabled. Typically, such an operation would come from an API.

Note

For errors related to CPU compatibility, see the VMware knowledge base article at http://kb.vmware.com/kb/1008027 for information on supported processors and guest operating systems. You can also use the VMware SiteSurvey utility (download at http://www.vmware.com/download/shared_utilities.html) to get a clearer understanding of the configuration issues associated with the cluster, host, and virtual machines being used for VMware FT.