When you set up a WSFC on VMware vSphere, see the checklists to configure your environment according to the requirements. You can also use the checklists to verify that your setup meets the requirements if you need technical support.

Requirements for Clustered Disks

Each type of clustered disk has its own requirements, depending on whether it is in a single-host cluster or multihost cluster.

Table 1. Requirements for Clustered Disks
Component Single-Host Clustering Multihost Clustering
Clustered VMDK SCSI bus sharing mode set to virtual is not supported. SCSI bus sharing mode set to physical is supported.
VMDK (In virtual compatibility mode) SCSI bus sharing mode set to virtual is supported. (Not Recommended) SCSI bus sharing mode set to Physical is not supported.

Device type must be set to virtual compatibility mode.

SCSI bus sharing mode must be set to virtual mode.

A single, shared RDM mapping file for each clustered disk is required.

Not supported.
pRDM Not supported.

RDM device type must be set to Physical compatibility mode during hard disk creation.

SCSI bus sharing mode of vSCSI Controller hosting pRDM must be set to physical.

A single, shared RDM mapping file for each clustered disk is required.

vVols storage Not Supported. SCSI bus sharing mode of vSCSI controller must be set to physical.
All types

All clustered nodes must use the same target SCSI ID (on the virtual SCSI adapter) for the same clustered disk.

A separate virtual SCSI adapter must be used for clustered disks.

Multiple virtual SCSI adapters for clustered disks (up to supported maximum) can be used to enhance performance. In this setup at least one controller should be dedicated to non-shared disk.

Other Requirements and Recommendations

The following table lists the components in your environment that have requirements for options or settings.

Table 2. Other Clustering Requirements and Recommendations
Component Requirement

Select Thick Provision with Eager zeroed during disk provisioning for VMDKs (for clustered VMDKs or VMDKs in virtual compatibility mode). For vVols select either thick or thin.

Modify the .vmx file for the WSFC VMs to add these lines:
  • scsiX.returnNoConnectDuringAPD = "TRUE"
  • scsiX.returnBusyOnNoConnectStatus = "FALSE"
  • Where X is the boot device SCSI bus controller ID number. By default, X is set to 0.

The only disks that you should not create with the Thick Provision option are RDM files (both physical and virtual compatibility mode).

Disk I/O timeout is 60 seconds or more (HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Disk\TimeOutValue).



  • Windows Server 2012
  • Windows Server 2012 R2
  • Windows Server 2016
  • Windows Server 2019 with vSphere 6.7 Update 3
  • Windows Server 2022 with vSphere 7.0

For Windows Server 2012 and above, you can use up to five cluster nodes.

Note: If you recreate the cluster, this value might be reset to its default, so you must change it again.

The cluster service must restart automatically on failure (first, second, and subsequent times).

Note: Windows Server 2008 and 2008 R2 have reached the end of extended support (no regular security updates). Consider the vendor support ability while hosting a WSFC on VMware vSphere.

Do not overcommit memory. Set the Memory Reservation (minimum memory) option to the same as the amount of memory assigned to the virtual machine.

ESXi uses a different technique to determine if Raw Device Mapped (RDM) LUNs are used for WSFC cluster devices, by introducing a configuration flag to mark each device as "perennially reserved" that is participating in an WSFC cluster. For ESXi hosts hosting passive WSFC nodes with RDM LUNs, use the esxcli command to mark the device as perennially reserved: esxcli storage core device setconfig -d <naa.id> --perennially-reserved=true. See KB 1016106 for more information.

Multipathing Contact your multipathing software vendor for information and support of non-VMware multipathing software in vSphere.

Required Information for Technical Support

The following table lists the files and settings to collect if you require technical support. Technical support uses these files and settings to analyze issues with a WSFC setup.

Note: Verify that your setup complies with the checklists in Requirements for Clustered Disks and Other Clustering Requirements and Recommendations before you contact technical support.
Table 3. Information Required by Technical Support
File or Information Description or Location
vm-support tarball Contains the vmkernel log, virtual machine configuration files and logs, and so on.
Application and system event logs of all virtual machines with the problem
Cluster log of all virtual machines with the problem %ClusterLog%, which is usually set to %SystemRoot%\cluster\cluster.log or use Get-ClusterLog Powershell CMdlet
Disk I/O timeout HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Disk\TimeOutValue
vSphere Client display names and Windows NETBIOS names of the virtual machines experiencing the problem
Date and time that the problem occurred
SAN configuration of the ESXi system Details about LUNs, paths, and adapters.
(Optional) Memory dump of the virtual machine Required if a guest virtual machine fails (a blue screen appears with an error message).