Search the VMware Knowledge Base (KB)
View by Article ID

Configuring Microsoft Cluster Service fails with the error: Validate SCSI-3 Persistent Reservation (1030632)

  • 14 Ratings


  • When attempting to set up a Microsoft Cluster, you receive an error in the Failover Cluster Validation Report during the validation step.

  • You see the error:

    One or more tests indicate that the configuration is not suitable for clustering.

  • In the Failover Cluster Validation Report, you see errors similar to:

    • Successfully put PR reserve on cluster disk 0 from node VIRTUAL_MACHINE_HOSTNAME.DOMAINNAME while it should have failed

    • Cluster Disk 0 does not support persistent reservations.


This issue can be caused by one of these situations:
  • If you are attempting to set up a Cluster in a Single Host, and the shared disk (or disks) for the cluster is RDM (Raw Device Mapping, or Raw Disk Mapping), in Physical Compatibility Mode. If this is the case, you can either change the disks to Virtual Compatibility mode, or if you wish to use Physical Compatibility Mode, the cluster nodes must be on different hosts.

  • If the storage array is not configured correctly to support SCSI-3 compliant commands.

  • A third-party plug-in is interfering with the SCSI reservation process (such as the PowerPath/VE PSA).

  • If virtual machines are running under the MSCS configuration on two separate ESX/ESXi hosts, and the .vmdk files are on a VMFS datastore which is configured as physical bus sharing mode. (This configuration of CAB is unsupported). For more information, see the Cluster Virtual Machines on One Physical Host section of the Setup for Failover Clustering and Microsoft Cluster Service Guide.


If you are attempting to create a cluster which is not one of these:
  • Cluster on a Single Host with one or more shared eagerzeroedthick virtual disks
  • Cluster on a Single Host with one or more shared RDMs in Virtual Compatibility mode
  • Cluster across Hosts with one or more shared RDMs in Physical Compatibility mode
Then you are not configuring a MSCS cluster with a supported configuration. For more/related information, see Microsoft Clustering on VMware vSphere: Guidelines for Supported Configurations (1037959) and Microsoft Cluster Service (MSCS) support on ESX/ESXi (1004617). It is critical that your configuration be set up consistent with the requirements specified in these articles.

If you are having issues with one of the supported MSCS configurations, resolve the issue with these steps:
  1. Remove all RDMs from the Windows 2008 virtual servers:
    1. Power off the virtual machine.
    2. Right-click the virtual machine and click Edit Settings.
    3. Take note of the RDM mapping.
    4. Remove the RDM hard disk from the virtual machine and click OK.

  2. Contact the storage vendor and make sure that the array has been configured correctly to support SCSI-3 compliant commands.

    Improvements in failover clusters require that the storage respond correctly to specific SCSI commands. The storage must follow the SPC-3 standard. In particular, the storage must support Persistent Reservations as specified in the SPC-3 standard.

  3. Add RDMs in physical compatibility (pass-through) mode or virtual compatibility (non-pass-through) mode. VMware recommends physical compatibility mode. For more information, see the Add Hard Disks to the First Node for Clusters Across Physical Hosts section of the Setup for Failover Clustering and Microsoft Cluster Service guide.
     4.  Ensure that relevant affinity/anti affinity rule is configured in a DRS cluster to prevent the virtual machines from powering on an incorrect host.
  • Cluster in a box should be on the same host affinity rule.
  • Cluster across box should be on separate hosts anti affinity.
  • When adding RDMs, select Physical as the compatibility mode and select a new virtual device node. For example: select SCSI (1:0).
  • If these steps do not resolve the issue, check for the existence of a third-party plug-in such as PowerPath/VE to determine if it is causing the issue. If you believe the issue may be related to PowerPath/VE, contact EMC for further assistance.
  • In vSphere 5.x, clusters across physical machines with non-pass-through RDM is supported only for clustering with Windows Server 2003. It is not supported for clustering with Windows Server 2008.

Additional Information

The same issue was seen in vCenter Server 5.5 and ESXi 5.5. EMC eventually confirmed that it is a known issue with EMC PowerPath VE prior to 5.9 SP1 P02. This is documented in its PowerPath VE 5.9 Release notes (Page 7 Problem 442177).

See Also

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.


  • 14 Ratings

Did this article help you?
This article resolved my issue.
This article did not resolve my issue.
This article helped but additional information was required to resolve my issue.

What can we do to improve this information? (4000 or fewer characters)

Please enter the Captcha code before clicking Submit.
  • 14 Ratings