What additional capability does Ganglia provide to monitor a Hadoop?

A.
Ability to monitor the amount of free space on HDFS.

B.
Ability to monitor number of files in HDFS.

C.
Ability to monitor processor utilization.

D.
Ability to monitor free task slots.

E.
Ability to monitor NameNode memory usage.

Explanation:
Ganglia itself collects metrics, such as CPU and memory usage; by using
GangliaContext, you can inject Hadoop metrics into Ganglia.
Note:
Ganglia is an open-source, scalable and distributed monitoring system for large clusters. It
collects, aggregates and provides time-series views of tens of machine-related metrics such as
CPU, memory, storage, network usage.
Ganglia is also a popular solution for monitoring Hadoop and HBase clusters, since Hadoop (and
HBase) has built-in support for publishing its metrics to Ganglia. With Ganglia you may easily see
the number of bytes written by a particular HDSF datanode over time, the block cache hit ratio for
a given HBase region server, the total number of requests to the HBase cluster, time spent in
garbage collection and many, many others.
Hadoop and HBase use GangliaContext class to send the metrics collected by each daemon
(such as datanode, tasktracker, jobtracker, HMaster etc) to gmonds.