Index: oak-store-composite/src/main/java/org/apache/jackrabbit/oak/composite/InitialContentMigrator.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- oak-store-composite/src/main/java/org/apache/jackrabbit/oak/composite/InitialContentMigrator.java	(revision d76aeb04babb7174016a05e083bbbb6a7636ce81)
+++ oak-store-composite/src/main/java/org/apache/jackrabbit/oak/composite/InitialContentMigrator.java	(date 1537944018000)
@@ -45,6 +45,8 @@
 import java.util.Set;
 
 import static org.apache.jackrabbit.oak.spi.cluster.ClusterRepositoryInfo.CLUSTER_CONFIG_NODE;
+import static org.apache.jackrabbit.oak.spi.namespace.NamespaceConstants.NAMESPACES_PATH;
+import static org.apache.jackrabbit.oak.spi.namespace.NamespaceConstants.REP_NSDATA;
 
 public class InitialContentMigrator {
 
@@ -52,7 +54,8 @@
 
     private static final String CLUSTER_ID = System.getProperty("oak.composite.seed.clusterId", "1");
 
-    private static final Set<String> DEFAULT_IGNORED_PATHS = ImmutableSet.of("/" + CLUSTER_CONFIG_NODE);
+    private static final Set<String> DEFAULT_IGNORED_PATHS = ImmutableSet
+        .of("/" + CLUSTER_CONFIG_NODE, NAMESPACES_PATH + "/" + REP_NSDATA);
 
     private static final Logger LOG = LoggerFactory.getLogger(InitialContentMigrator.class);
 
Index: oak-store-composite/src/test/java/org/apache/jackrabbit/oak/composite/InitialContentMigratorTest.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- oak-store-composite/src/test/java/org/apache/jackrabbit/oak/composite/InitialContentMigratorTest.java	(revision d76aeb04babb7174016a05e083bbbb6a7636ce81)
+++ oak-store-composite/src/test/java/org/apache/jackrabbit/oak/composite/InitialContentMigratorTest.java	(date 1537944018000)
@@ -16,7 +16,11 @@
  */
 package org.apache.jackrabbit.oak.composite;
 
+import static org.apache.jackrabbit.JcrConstants.JCR_SYSTEM;
 import static org.apache.jackrabbit.oak.spi.cluster.ClusterRepositoryInfo.CLUSTER_CONFIG_NODE;
+import static org.apache.jackrabbit.oak.spi.namespace.NamespaceConstants.NAMESPACES_PATH;
+import static org.apache.jackrabbit.oak.spi.namespace.NamespaceConstants.REP_NAMESPACES;
+import static org.apache.jackrabbit.oak.spi.namespace.NamespaceConstants.REP_NSDATA;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
@@ -70,11 +74,15 @@
         
         root = seed.getRoot().builder();
         root.child("third");
+        root.child(JCR_SYSTEM).child(REP_NAMESPACES).child(REP_NSDATA);
+
         seed.merge(root, EmptyHook.INSTANCE, CommitInfo.EMPTY);
         
         MemoryNodeStore target = new MemoryNodeStore();
         NodeBuilder targetRootBuilder = target.getRoot().builder();
         targetRootBuilder.child(CLUSTER_CONFIG_NODE);
+        targetRootBuilder.child(JCR_SYSTEM).child(REP_NAMESPACES);
+
         target.merge(targetRootBuilder, EmptyHook.INSTANCE, CommitInfo.EMPTY);
 
         MountInfoProvider mip = Mounts.newBuilder().mount("seed", "/first").build();
@@ -90,6 +98,8 @@
         assertTrue("Node /second should have been migrated", targetRoot.hasChildNode("second"));
         assertTrue("Node /third should have been migrated", targetRoot.hasChildNode("third"));
         assertTrue(CLUSTER_CONFIG_NODE  + " should be retained", targetRoot.hasChildNode(CLUSTER_CONFIG_NODE));
+        assertFalse(NAMESPACES_PATH + "/" + REP_NSDATA + " should not be copied",
+            targetRoot.getChildNode(JCR_SYSTEM).getChildNode(REP_NAMESPACES).hasChildNode(REP_NSDATA));
 
         // verify that the 'second' node is visible in the migrated store when retrieving the checkpoint
         NodeState checkpointTargetRoot = target.retrieve(checkpoint1);