After the services have started, verify that rack awareness has been activated by
looking in the NameNode logs located in /var/log/hadoop/hdfs/ (for example:
hadoop-hdfs-namenode-sandbox.log). You should see an entry like this:
014-01-13 15:58:08,495 INFO org.apache.hadoop.net.NetworkTopology: Adding a new node: /rack01/<ipaddress>
Also, the Hadoop fsck command should return something like the following
(if there are two racks):
Status: HEALTHY Total size: 123456789 B Total dirs: 0 Total files: 1 Total blocks (validated): 1 (avg. block size 123456789 B) Minimally replicated blocks: 1 (100.0 %) Over-replicated blocks: 0 (0.0 %) Under-replicated blocks: 0 (0.0 %) Mis-replicated blocks: 0 (0.0 %) Default replication factor: 3 Average block replication: 3.0 Corrupt blocks: 0 Missing replicas: 0 (0.0 %) Number of data-nodes: 40 Number of racks: 2 FSCK ended at Mon Jan 13 17:10:51 UTC 2014 in 1 milliseconds
