VMware SRM Planned Failover Warnings for VMs with RDM Disks

Products

• VMware Live Recovery

Issue/Introduction

Symptoms : 

• Performing a SRM Test Failover, the following warnings are observed in the Recovery Plan:
  

  Warning - The live migration of the virtual machine 'VM_Name' in the protection group 'PG_Name' from the protected site to the recovery site would fail if a planned failover were to be performed now. 
  It is recommended to resolve host compatibility issues as soon as possible to minimize the risk of live migration failures during a planned failover. The virtual disk with the key 'xxxx' of the virtual machine 'VM_Name' uses a raw disk backing, which is not supported for xVC-vMotion.

• Test failover completes successfully, but warnings are shown for VMs that have Raw Device Mappings (RDMs).
  
  
• The warnings only appear when planned failover is validated.
  
  
• The environment supports stretched storage.

Environment

VMware Live Site Recovery 9.0.X Appliance

Cause

The warning is seen because in stretched storage supported environments, SRM planned failover relies on cross-vCenter vMotion (xVC-vMotion) for seamless, zero-downtime migration of VMs between sites.

RDM-backed disks are not supported for xVC-vMotion (cross-vCenter vMotion)

Resolution

As per 'How VMware Live Site Recovery Interacts with Stretched Storage'  Document :

Cross vCenter Server vMotion does not work in these situations.

• If the distributed resource scheduler is deactivated for the cluster
• If the virtual machine has snapshots
• If the virtual machine is a linked clone
• If the virtual machine is attached to RDM devices

Therefore, SRM cannot live migrate these VMs. Instead, SRM will perform a shutdown at the protected site and a power-on at the recovery site. This is a vSphere platform limitation, not a product defect.

Refer KB # 404950 - VMs with RDMs fail to migrate across vCenters for more details. 

Note : When running the Failover run test, ensure the "Enable vMotion of eligible VMs" option is unchecked when RDM VMs is in use. 

Example :