Rebalance didn't trigger after exiting the host from maintenance

Products

• VMware vSAN

Issue/Introduction

• Host which was in maintenance mode for a long time, didn't trigger data rebalance after existing the host from maintenance mode.
  
  
• Adding a new host to the vSAN cluster might also not trigger any data rebalance.
  
  
• In vCenter UI, Cluster > Monitor > vSAN > Skyline health will report warning for 'vSAN Disk rebalance'.
  
  
  
  
• In vCenter UI, Cluster > Manage > vSAN > Disk Management will show the new added host is having very less space utilization when compared to other hosts in the cluster.
  
  

Environment

VMware vSAN

Cause

Rebalance will not triggered if the Automatic rebalance was not enabled for the cluster. When Automatic rebalance is enabled, vSAN will automatically move the data from the higher utilized disk to the lower utilized disk. If this is not enabled, vSAN will only initiate rebalance on vSAN disks when any of the vSAN disks crosses 80% Capacity threshold.


From vCenter UI, Cluster > Configure > vSAN > Services > Advanced Options will show the Automatic rebalance is not enabled.

Resolution

Enable Automatic rebalance on the cluster to fix this issue.

Follow the below article to configure the Automatic rebalance.
Configure Automatic Rebalance in vSAN Cluster

Additional Information

vSAN "Proactive rebalance" and "Automatic Rebalance"