Storage DRS causing automated migration of VMDKs back to original location after Storage vMotion

Products

• VMware vSphere ESXi

Issue/Introduction

When performing Storage vMotion on Virtual Machine (VM) by selecting "custom" locations for individual hard disks, the VMDK files successfully migrate but shortly thereafter move back to the source datastore automatically.

The vSphere Client "Tasks" pane shows: "Storage DRS migrated disks of VM to datastore" immediately following a manual migration.

 

Environment

VMware vSphere ESXi

VMware vCenter

Cause

This behavior is caused by the Default VM Affinity rule being enabled within the Storage DRS configuration under Advanced Options.

Default VM affinity rule when enabled keeps VMDKs together by default which means each VM in the datastore cluster will have its virtual disks on the same datastore by default. Hence, DRS try to move VMDKs back to the source datastore.

Resolution

To allow for custom disk placement,  disable the default VM affinity rule, by following the below steps: 

• Navigate to the Datastore Cluster in the vSphere Inventory.
• Go to the Configure tab.
• Under Services, select Storage DRS.
• Click Edit.
• Navigate to  Advanced Options.
• Locate Default VM affinity (Keep virtual disks together by default) rule. 
• Uncheck the box to disable the rule.
• Click OK.

Retry the Storage vMotion using the "Configure per disk" option.