Cannot unmount a datastore that resided on a LUN that has been removed from the array.

Products

• VMware vSphere ESXi

Issue/Introduction

If a LUN has been removed from the array then none of the hosts will be able to send a command to unmount the datastore that previously resided on that LUN.

Symptoms: 

• The datastore will show "inaccessible" in the vCenter inventory and on the Host UI.
• The LUN has been removed from the storage device. 

Environment

• vSphere 8.0.x
• vSphere 7.0.x
• vSphere 6.x.x

Cause

If you removed the backing LUN intentionally or due to hardware failure then we need to remove all reference to this datastore from hosts and vCenter. In this situation we cannot ask the LUN to unmount the datastore from the host since the LUN no longer exists. 

Resolution

To resolve this issue you can try rescanning the datastore from the cluster level: 

• Navigate to vCenter
• Right click the cluster 
• Select Storage>Rescan 

If this does not remove the datastore from the inventory then you will need to do a rolling reboot of all hosts that connected to that device. This will remove any connections from the host to the datastore.

If you still see the datastore in the vCenter inventory, you will need to manually removing an ESXi host from the vCenter Server database. This will remove any connections from the vCenter Server to the datastore. 

 

Additional Information

• To unmount and detach a LUN normally see: How to detach a LUN device from ESXi hosts
• If the LUN is inaccessible but should still be physically connected to the array with no hardware issues see: Troubleshooting LUN connectivity issues on ESXi hosts
• To remove references to the LUN within the VCDB see:  Manually removing an ESXi host from the vCenter Server database