You receive the following event message when a storage device containing a datastore becomes permanently unavailable to the ESXi host as a result of a permanent loss:
Device :device has been removed or is permanently inaccessible while holding a reservation.
The message indicates that the permanent device loss occurred while the device was reserved for exclusive use by the ESXi host.
Impact
When a permanent device loss occurs during a datastore operation that requires a SCSI reservation, the operation fails and the datastore becomes unavailable. ESXi marks the device as not connected and a warning about the device being permanently unavailable appears in the VMkernel log file.