hbtop

A top-like monitor could be useful for testing, debugging, operations of clusters of moderate size, and possibly for diagnosing issues in large clusters.

Consider a curses interface like the one presented by atop (http://www.atoptool.nl/images/screenshots/genericw.png) - with aggregate metrics collected over a monitoring interval in the upper portion of the pane, and a listing of discrete measurements sorted and filtered by various criteria in the bottom part of the pane. One might imagine a cluster overview with cluster aggregate metrics above and a list of regionservers sorted by utilization below; and a regionserver view with process metrics above and a list of metrics by operation type below, or a list of client connections, or a list of threads, sorted by utilization, throughput, or latency.

Generically 'htop' is taken but would be distinctive in the HBase context, a utility org.apache.hadoop.hbase.HTop

No need necessarily for a curses interface. Could be an external monitor with a web front end as has been discussed before. I do like the idea of a process that runs in a terminal because I interact with dev and test HBase clusters exclusively by SSH.

UPDATE:
The tool name is changed from htop to hbtop.