Storage DRS is unable to balance VMs across datastores

Products

• VMware vCenter Server

Issue/Introduction

• Storage DRS is unable to balance VMs across datastore or balance datastore IOPS reservation
  
  
• When selecting "Run SDRS now", Storage DRS Faults are observed
  
  
• The available storage IOs capacity is not sufficient for the operation
  
  
• The errors in the SDRS faults area will look similar to this:
  
  

Environment

VMware vCenter Server 7.0.x

Cause

SDRS iOPS calculation has errors present in releases prior to 7.0 U3o.

Resolution

This issue is fixed in vSphere 7.0 U3o (P08).

Workaround

Option 1: If IO reservation is not needed.

1. Disable "Enable IO metric for SDRS recommendation"
2. Set SDRS advance option "EnforceIOReservations" to 0
3. Set SDRS advance option "EnableIoLoadBalancing" to 0

Option 2: If IO reservation is needed.

1. Enable "Enable IO metric for SDRS recommendation"

Additional Information

VMware vCenter Server 7.0 Update 3o Release Notes