svn merge -c 1483150 from trunk for HDFS-4826. TestNestedSnapshots times out due to repeated slow edit log flushes when running on virtualized disk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1488090 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -122,6 +122,9 @@ Release 2.0.5-beta - UNRELEASED
     HDFS-4698. Provide client-side metrics for remote reads, local reads, and
     short-circuit reads. (Colin Patrick McCabe via atm)
 
+    HDFS-4826. TestNestedSnapshots times out due to repeated slow edit log
+    flushes when running on virtualized disk.  (Chris Nauroth via szetszwo)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestNestedSnapshots.java

@@ -36,6 +36,7 @@ import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.NSQuotaExceededException;
+import org.apache.hadoop.hdfs.server.namenode.EditLogFileOutputStream;
 import org.apache.hadoop.hdfs.server.namenode.FSDirectory;
 import org.apache.hadoop.hdfs.server.namenode.INode;
 import org.apache.hadoop.hdfs.server.namenode.INodeDirectory;
@@ -48,6 +49,12 @@ import org.junit.Test;
 
 /** Testing nested snapshots. */
 public class TestNestedSnapshots {
+  static {
+    // These tests generate a large number of edits, and repeated edit log
+    // flushes can be a bottleneck.
+    EditLogFileOutputStream.setShouldSkipFsyncForTesting(true);
+  }
+
   {
     SnapshotTestHelper.disableLogs();
   }