"An error occurred while communicating with the remote host" error seen while unmounting a datastore

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms-

• Underlying LUN for the datastore is already unpresented from storage side.
  
  
• Inaccessible datastore entry on vCenter.
  
  
  
• Rescanning storage from vCenter gives an error "An error occurred while communicating with the remote host".
  
  
  
• Running below commands on the host doesn't list any stale/running services -
  [root@ESX:~] lsof | grep <Datastore Name>
[root@ESX:~] lsof | grep <Datastore UUID>
[root@ESX:~] lsof | grep <LUN name>
[root@ESX:~] esxcli storage core device world list -d <LUN name>

Environment

• VMware vSphere ESXi 7.x
• VMware vSphere ESXi 8.x

Cause

• LUNs are directly unmapped from the storage array instead of following proper procedure highlighted in KB - How to detach a LUN device from ESXi hosts

Resolution

Before proceeding with the steps below, take both a backup and a snapshot of the vCenter Server Appliance. If the vCenter is part of a Enhanced Linked Mode (ELM) replication setup, also take a backup or offline (powered off) snapshot of all replicating vCenter ELM nodes.

• Reboot the host.
• If issue persists then reboot vCenter.
• If the issue still persists then follow Unable to remove inaccessible datastore entry from vCenter, to remove the stale datastore entry from the vCenter Database.