Minor Description
Datanode storage ID used to use IP and port. It has changed to use UUID. This makes debugging harder when we want to understand which DNs are assigned when DFSClient calls addBlock. For example,
BLOCK* allocateBlock: /foo. BP-1980237412-xx.xx.xxx.xxx-1408142057773 blk_1227779764_154043834{blockUCState=UNDER_CONSTRUCTION, primaryNodeIndex=-1, replicas=[ReplicaUnderConstruction[[DISK]DS-9479727b-24c5-4068-8703-dfb9a41c056c:NORMAL|RBW], ReplicaUnderConstruction[[DISK]DS-abe7840c-1db8-4623-9da7-3aed6a28c4f4:NORMAL|RBW], ReplicaUnderConstruction[[DISK]DS-956023f4-56a0-4c30-a148-b78c61cf764b:NORMAL|RBW]]}