Re: VMFS Datastores showing inactive for some of ESXi hosts(ESXi 5.5.0 build-1746018) in vCenter. Cannot unmount the datastore through GUI or commandline

Hi,

Above message indicates that An unplanned PDL occured  when the storage device would have been unexpectedly unpresented from the storage array without the unmount and detach being executed on the ESXi host..This also happens if the LUN ran out space causing it to become inaccessible.

If you are unable to unmount the datastore , try the following steps:

1. Confirm that there is no I/O queued to the LUN and that it is not a snapshot LUN.

For this all running virtual machines from the datastore must be powered off and unregistered from the vCenter Server.

2.Unpresent the LUN from the storage.

3.Rescan. This will unmount the LUN.

4,Represent from the storage.

5.Re-mount the LUN on the host(s).