The API added in
HDFS-811 for the DN to report volume failures to the NN is "inc(DN)". However the given sequence of events will result in the NN forgetting about reported failed volumes:
- DN loses a volume and reports it
- NN restarts
- DN re-registers to the new NN
A more robust interface would be to have the DN report the total number of volume failures to the NN each heart beat (the same way other volume state is transmitted).