Question : LUN unpresented from ESX hosts causing alarms

After I unpresented a LUN from my ESX servers, I started receiving vCenter alarms that read "[VMware vCenter - Alarm Cannot connect to storage] Lost connectivity to storage device ". There were *never* any vmdks on on this LUN and it was never added as a datastore. I did perform an HBA rescan to make sure the LUN was visible on the storage adapters view but never added it as a disk to any VM or create a datastore on it.

So, since it was never initialized or used, I simply unpresented that LUN from all of my ESX hosts. Now I am constantly getting the alarms from vCenter because the ESX hosts cannot see that LUN. To make matters worse, I have since presented a new LUN to my hosts and it now has the same LUN number as the previous LUN but with a different naa number.

How can I clean this up?

Answer : LUN unpresented from ESX hosts causing alarms

Have you tried rebooting vCenter Server? Sometimes things like that get hung in the vCenter DB and reboot clears it up. Rebooting VC won't cause any VMs to go down. You will get kicked outta your vSphere Client though, if you're logged into vCenter.

~coolsport00