The Hadoop Name Node Layer

The tests mapped to this layer:

  • Capture corrupt and missing blocks;
  • Measure how quickly the Secondary NameNode downloads EditLogs from the NameNode, and how quickly the NameNode uploads and downloads FsImages from the Secondary NameNode;
  • Warn administrators of slowness in Journal transactions that may potentially impact cluster availability;
  • Alert you to the poor usage of the retry cache;
  • Identify the exact RPC interface that is overloaded with connections, and proactively detect RPC processing bottlenecks on the NameNode;
  • Quickly detect unscheduled reboots of the NameNode;
  • Track administrator- and user-initiated snapshot operations on the HDFS;
  • Monitor how storage space is used across a cluster, and be proactively alerted if the cluster is running out of space