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vSAN proactive rebalance (2149809)

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The purpose of this article is to explain vSAN proactive rebalance and when it may be applicable.

If disks show up with with errors in the health check saying that the cluster is imbalanced and there are disks that are high on space usage while others are very low, you may need to run a proactive rebalance. This manually initiates a rebalance of the objects in a vsan cluster.


Running a manual rebalance may be necessary when your vSAN cluster is imbalanced. This operation moves components from the over-utilized disks to the under-utilized disks. 

Note: Running a manual rebalance does utilize some system resources and this process can take several hours to complete depending on how badly imbalanced objects are, so the performance impact must be considered when deciding when to run this process.

To run a proactive rebalance in vSphere 6.5 and later:
  1. Navigate to the vSAN cluster in the vSphere Web Client.
  2. Click the Monitor tab and click vSAN.
  3. Click Health.
  4. In the vSAN health service table, select Warning: Virtual SAN Disk Balance. You can review the disk balance of the hosts.
  5. Click the Rebalance Disks button to rebalance your cluster. 
    Note: This task may take many hours.
To run the proactive rebalance in releases prior to vSphere 6.5:
  1. Log into the Ruby vSphere Console (RVC).
  2. Change to the computers namespace.
  3. To see how much data needs to be rebalanced, Run this command on your vSAN cluster:
    vsan.proactive_rebalance_info <vSAN-cluster-number>

  4. To start the rebalance, run this command:
    vsan.proactive_rebalance -s <vSAN-cluster-number> 

  5. Monitor the status of the rebalance using this command:
    vsan.proactive_rebalance_info <vSAN-cluster-number>

    Note: This task may take many hours.

Additional Information

For more information about:

Update History

08/04/2017 - Added vSAN 6.6 to Products, Added vSphere Web Client steps.

Request a Product Feature

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