HDFS-4021. Misleading error message when resources are low on the NameNode. Contributed by Christopher Conner.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1396881 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -316,6 +316,9 @@ Release 2.0.3-alpha - Unreleased
 
     HDFS-4020. TestRBWBlockInvalidation may time out. (eli)
 
+    HDFS-4021. Misleading error message when resources are low on the NameNode.
+    (Christopher Conner via atm)
+
 Release 2.0.2-alpha - 2012-09-07 
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -4059,7 +4059,10 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
         return "Safe mode is OFF.";
       String leaveMsg = "";
       if (areResourcesLow()) {
-        leaveMsg = "Resources are low on NN. Safe mode must be turned off manually";
+        leaveMsg = "Resources are low on NN. " 
+        	+ "Please add or free up more resources then turn off safe mode manually.  "
+        	+ "NOTE:  If you turn off safe mode before adding resources, "
+        	+ "the NN will immediately return to safe mode.";
       } else {
         leaveMsg = "Safe mode will be turned off automatically";
       }