VMDK affinity rules indicate that all virtual disks in a datastore cluster that are associated with a particular virtual machine are located on the same datastore in the datastore cluster. The rules apply to individual datastore clusters.

VMDK affinity rules are activated by default for all virtual machines that are in a datastore cluster. You can override the default setting for the datastore cluster or for individual virtual machines.

Virtual machines that are subject to VMDK affinity rules have the following behavior:

  • Storage DRS places the virtual machine's virtual disks according to the rule.
  • Storage DRS migrates the virtual disks using vMotion according to the rule, even if the migration is for a mandatory reason such as putting a datastore in maintenance mode.
  • If the virtual machine's virtual disk violates the rule, Storage DRS makes migration recommendations to correct the error or reports the violation as a fault if it cannot make a recommendation that will correct the error.

When you add a datastore to a datastore cluster that is activated for Storage DRS, the VMDK affinity rule is deactivated for any virtual machine that has virtual disks on that datastore if it also has virtual disks on other datastores.


  1. Browse to the datastore cluster in the vSphere Client.
  2. Click the Configure tab and click Configuration.
  3. Select VM Overrides.
  4. Click Add.
  5. Use the + button to select virtual machines.
  6. Click the Keep VMDKs together drop-down menu and select No.
  7. Click OK.