Viewing a List of Volumes

You can view all volumes using the volume list command, or you can view them in the MapR Control System.

To view all volumes using the MapR Control System, expand the MapR-FS group and click the Volumes view in the Navigation pane.

If you have a fresh MapReduce Classic (MapReduce1) installation and configuration, the following volumes appear:

Local volumes

<nodename1>.local.audit
mapr.<nodename1>.local.logs
mapr.<nodename1>.local.mapre
mapr.<nodename1>.local.metrics
.
.
.
mapr.<nodenamen>.local.audit
mapr.<nodenamen>.local.logs
mapr.<nodenamen>.local.mapred
mapr.<nodenamen>.local.metrics 
The <nodenamen> represents local volumes that bear the names of each node in the cluster.
Mounted system volumes
mapr.cluster.root
mapr.configuration
mapr.hbase
mapr.jobtracker.volume
mapr.metrics mapr.opt
mapr.tmp
mapr.var
users
Unmounted system volumes
mapr.cldb.internal
If you have a fresh YARN (MapReduce2) installation and configuration, the list includes all of these volumes, except the mapr.jobtracker.volume, and also includes the following system volume.
YARN system volume
mapr.resourcemanager.volume
If you have a fresh mixed-mode installation and configuration, the list of includes all of these volumes.

The mapr.jobtracker.volume and mapr.resourcemanager.volume require special handling. Proper planning and sizing of these volumes is critical to cluster health.