FSNamesystem namesystem = cluster.getNameNode().namesystem;
// Ensure the data reported for each data node is right
ArrayList<DatanodeDescriptor> live = new ArrayList<DatanodeDescriptor>();
ArrayList<DatanodeDescriptor> dead = new ArrayList<DatanodeDescriptor>();
namesystem.DFSNodesStatus(live, dead);
assertTrue(live.size() == 1);
long used, remaining, configCapacity, nonDFSUsed, nsUsed;
float percentUsed, percentRemaining, percentNSUsed;