[HDFS-7283] Bump DataNode OOM log from WARN to ERROR

• Type: Improvement
• Status: Closed
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 2.0.0-alpha
• Fix Version/s: 2.7.0
• Component/s: datanode
• Labels: supportability
• Target Version/s: 2.7.0
• Hadoop Flags: Reviewed
• Assignee: Stephen Chu
• Reporter: Stephen Chu
• Created: 23/Oct/14 20:06
• Updated: 06/May/15 17:10
• Resolved: 24/Oct/14 17:50

Description

When the DataNode OOMs, it logs the following WARN message which should be bumped up to ERROR because DataNode OOM often leads to DN process abortion.

WARN org.apache.hadoop.hdfs.server.datanode.DataNode: DataNode is out of memory. Will retry in 30 seconds. 
4751 java.lang.OutOfMemoryError: unable to create new native thread"

Thanks to Roland Teague for identifying this.