diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java index 6f76dc03f9..4b2058bbcf 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java +++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java @@ -899,7 +899,7 @@ public class DFSConfigKeys extends CommonConfigurationKeys { public static final String DFS_IMAGE_PARALLEL_LOAD_KEY = "dfs.image.parallel.load"; - public static final boolean DFS_IMAGE_PARALLEL_LOAD_DEFAULT = true; + public static final boolean DFS_IMAGE_PARALLEL_LOAD_DEFAULT = false; public static final String DFS_IMAGE_PARALLEL_TARGET_SECTIONS_KEY = "dfs.image.parallel.target.sections"; diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml b/hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml index 69017dfa77..d2ca0af59e 100755 --- a/hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml +++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml @@ -1393,7 +1393,7 @@ dfs.image.parallel.load - true + false If true, write sub-section entries to the fsimage index so it can be loaded in parallel. Also controls whether parallel loading @@ -1403,6 +1403,11 @@ Parallel loading is not compatible with image compression, so if dfs.image.compress is set to true this setting will be ignored and no parallel loading will occur. + Enabling this feature may impact rolling upgrades and downgrades if + the previous version does not support this feature. If the feature was + enabled and a downgrade is required, first set this parameter to + false and then save the namespace to create a fsimage with no + sub-sections and then perform the downgrade.