You can use Site Recovery Manager to protect Windows Server Failover Clustering (WSFC) and fault tolerant virtual machines, with certain limitations.
To use Site Recovery Manager to protect WSFC and fault tolerant virtual machines, you might need to change your environment.
General Limitations to Protecting WSFC and Fault Tolerant Virtual Machines
Protecting WSFC and fault tolerant virtual machines is subject to the following limitations.
- You can use array-based replication only to protect WSFC virtual machines. Protecting WSFC virtual machines with vSphere Replication is not supported.
- Protect and reprotect of WSFC or fault tolerant virtual machines requires VMware High Availability (HA) and VMware Distributed Resource Scheduler (DRS) at both the protected and the recovery sites. When you move WSFC or fault tolerant virtual machines across their primary and secondary sites during reprotect, you must enable HA and DRS, and set the affinity and antiaffinity rules as appropriate. See DRS Requirements for Protection of WSFC Virtual Machines.
- You can use array-based replication to protect multiple vCPU fault tolerance (SMP-FT) virtual machines. Both the primary and the secondary fault tolerant virtual machine disk files must reside on replicated LUNs, and all LUNs must be part of the same consistency group.
- Site Recovery Manager attempts to fail over only the primary SMP-FT virtual machine and does not try to fall back on the secondary SMP-FT virtual machine, if something is wrong with the files of the primary SMP-FT virtual machine.
- Site Recovery Manager shows a warning when an SMP-FT VM virtual machine is protected and its storage does not meet the replication requirements.
- One SMP-FT virtual machine can be protected by only one Protection Group.
- Site Recovery Manager does not support for SMP-FT virtual machines replicated by vSphere Replication.
- Site Recovery Manager does not support SMP-FT virtual machines in storage policy protection groups. SMP-FT does not support storage profiles.
- Site Recovery Manager does not support recovery of SMP-FT virtual machines with Virtual Volumes protection groups. SMP-FT does not support storage profiles.
- When doing reprotect, Site Recovery Manager does not preserve SMP-FT configuration on the original protected site.
- When performing failover, the destination virtual machine is powered on as non-FT virtual machine. It can be configured as an SMP-FT virtual machine after failover by using tools outside Site Recovery Manager.
- Fault tolerant virtual machines are not supported on NFS datastores.
ESXi Host Requirements for Protection of WSFC Virtual Machines
To protect WSFC or fault tolerant virtual machines, the ESXi host machines on which the virtual machines run must meet certain criteria.
- You can run a cluster of WSFC virtual machines in the following possible configurations.
- The WSFC virtual machines in the cluster run on a single ESXi host. You can have a maximum of five WSFC nodes on one ESXi host.
- You can spread the WSFC cluster across a maximum of five ESXi host instances. You can protect only one virtual machine node of any WSFC cluster on a single ESXi host instance. You can have multiple WSFC node virtual machines running on an ESXi host, if they do not participate in the same WSFC cluster. This configuration requires shared storage on a Fibre Channel SAN for the quorum disk.
DRS Requirements for Protection of WSFC Virtual Machines
To use DRS on sites that contain WSFC virtual machines, you must configure the DRS rules to allow Site Recovery Manager to protect the virtual machines. By following the guidelines, you can protect WSFC virtual machines on sites that run DRS if the placeholder virtual machines are in either a cluster-across-boxes WSFC deployment or in a cluster-in-a-box WSFC deployment.
- Set the DRS rules on the virtual machines on the protected site before you configure MSCS in the guest operating systems. Set the DRS rules immediately after you deploy, configure, or power on the virtual machines.
- Set the DRS rules on the virtual machines on the recovery site immediately after you create a protection group of WSFC nodes, as soon as the placeholder virtual machines appear on the recovery site.
- DRS rules that you set on the protected site are not transferred to the recovery site after a recovery. For this reason, you must set the DRS rules on the placeholder virtual machines on the recovery site.
- Do not run a test recovery or a real recovery before you set the DRS rules on the recovery site.
If you do not follow the guidelines on either the protected site or on the recovery site, vSphere vMotion might move WSFC virtual machines to a configuration that Site Recovery Manager does not support.
- In a cluster-in-a-box deployment on either the protected or recovery site, vSphere vMotion might move WSFC virtual machines to different ESXi hosts.
- In a cluster-across-boxes deployment on either the protected or recovery site, vSphere vMotion might move some or all of the WSFC virtual machines to a single ESXi host.
Support for WSFC with Clustered VMDKs
Site Recovery Manager can protect WSFC with clustered virtual machine disk files. vSphere 7.0 introduces support for the use of VMDKs on a clustered datastore as shared disk resources for a WSFC. Using VMDKs reduces the extra overhead to manage the virtual disks compared to pRDMs. For additional information about the supported configurations for a WSFC with shared disk resources, see Setup for Windows Server Failover Clustering in the VMware vSphere Product Documentation.