How to retrive ambari HDFS disk usage metrics

Hi all i am trying to retrieve ambari metrics. if any one know please reply.

for example if i call bellow Rest API i will get CPU utilization data in JSON:
http://<ambari-server&gt;:8080/api/v1/clusters/<cluster-name>?fields=metrics/cpu[1430844925,1430848525,15]&_=1430848532904

if i call bellow Resr APi i will get network usage data in JSON.
http://<ambari-server&gt;:8080/api/v1/clusters/<cluster-name>?fields=metrics/network[1430844925,1430848525,15]&_=1430848532904

same as above i want how to retrieve ”HDFS disk usage metrics data’.
if any one know help me out.

Thanks in advance.