HDFS-4227. Document dfs.namenode.resource.* (Daisuke Kobayashi via aw)

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -981,6 +981,8 @@ Release 2.6.0 - UNRELEASED
     HDFS-6664. HDFS permissions guide documentation states incorrect default 
     group mapping class. (Ray Chiang via aw)
 
+    HDFS-4227. Document dfs.namenode.resource.*  (Daisuke Kobayashi via aw)
+
 Release 2.5.1 - 2014-09-05
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml

@@ -633,6 +633,44 @@
   </description>
 </property>
 
+<property>
+  <name>dfs.namenode.resource.check.interval</name>
+  <value>5000</value>
+  <description>
+    The interval in milliseconds at which the NameNode resource checker runs.
+    The checker calculates the number of the NameNode storage volumes whose
+    available spaces are more than dfs.namenode.resource.du.reserved, and
+    enters safemode if the number becomes lower than the minimum value
+    specified by dfs.namenode.resource.checked.volumes.minimum.
+  </description>
+</property>
+
+<property>
+  <name>dfs.namenode.resource.du.reserved</name>
+  <value>104857600</value>
+  <description>
+    The amount of space to reserve/require for a NameNode storage directory
+    in bytes. The default is 100MB.
+  </description>
+</property>
+
+<property>
+  <name>dfs.namenode.resource.checked.volumes</name>
+  <value></value>
+  <description>
+    A list of local directories for the NameNode resource checker to check in
+    addition to the local edits directories.
+  </description>
+</property>
+
+<property>
+  <name>dfs.namenode.resource.checked.volumes.minimum</name>
+  <value>1</value>
+  <description>
+    The minimum number of redundant NameNode storage volumes required.
+  </description>
+</property>
+
 <property>
   <name>dfs.datanode.balance.bandwidthPerSec</name>
   <value>1048576</value>