HDFS-10297. Increase default balance bandwidth and concurrent moves. Contributed by John Zhuge.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java

@@ -87,9 +87,12 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final String  DFS_NAMENODE_BACKUP_SERVICE_RPC_ADDRESS_KEY = "dfs.namenode.backup.dnrpc-address";
   public static final String  DFS_DATANODE_BALANCE_BANDWIDTHPERSEC_KEY =
       HdfsClientConfigKeys.DeprecatedKeys.DFS_DATANODE_BALANCE_BANDWIDTHPERSEC_KEY;
-  public static final long    DFS_DATANODE_BALANCE_BANDWIDTHPERSEC_DEFAULT = 1024*1024;
-  public static final String  DFS_DATANODE_BALANCE_MAX_NUM_CONCURRENT_MOVES_KEY = "dfs.datanode.balance.max.concurrent.moves";
-  public static final int     DFS_DATANODE_BALANCE_MAX_NUM_CONCURRENT_MOVES_DEFAULT = 5;
+  public static final long    DFS_DATANODE_BALANCE_BANDWIDTHPERSEC_DEFAULT =
+      10 * 1024*1024;
+  public static final String  DFS_DATANODE_BALANCE_MAX_NUM_CONCURRENT_MOVES_KEY
+      = "dfs.datanode.balance.max.concurrent.moves";
+  public static final int
+      DFS_DATANODE_BALANCE_MAX_NUM_CONCURRENT_MOVES_DEFAULT = 50;
   @Deprecated
   public static final String  DFS_DATANODE_READAHEAD_BYTES_KEY =
       HdfsClientConfigKeys.DFS_DATANODE_READAHEAD_BYTES_KEY;

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

@@ -856,7 +856,7 @@
 
 <property>
   <name>dfs.datanode.balance.bandwidthPerSec</name>
-  <value>1048576</value>
+  <value>10m</value>
   <description>
         Specifies the maximum amount of bandwidth that each datanode
         can utilize for the balancing purpose in term of
@@ -3409,7 +3409,7 @@
 
 <property>
   <name>dfs.datanode.balance.max.concurrent.moves</name>
-  <value>5</value>
+  <value>50</value>
   <description>
     Maximum number of threads for Datanode balancer pending moves.  This
     value is reconfigurable via the "dfsadmin -reconfig" command.