when {HEAD ~ the data migration} from {TAIL ~ the first storage} to the second storage is completed, notifying by the data migration node the one or more network devices in the network that traffic that is received by the network devices is no longer to be routed to the data migration node; and 
from
when { HEAD ~ the data migration } from { TAIL ~ the first storage } to the second storage is completed , notifying by the data migration node the one or more network devices in the network that traffic that is received by the network devices is no longer to be routed to the data migration node ; and
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH