diff --git a/scm-webapp/src/main/java/sonia/scm/update/repository/BaseMigrationStrategy.java b/scm-webapp/src/main/java/sonia/scm/update/repository/BaseMigrationStrategy.java
index 27d8732b17..ef2624eadd 100644
--- a/scm-webapp/src/main/java/sonia/scm/update/repository/BaseMigrationStrategy.java
+++ b/scm-webapp/src/main/java/sonia/scm/update/repository/BaseMigrationStrategy.java
@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.update.repository;
 
 import sonia.scm.SCMContextProvider;
@@ -31,6 +31,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Arrays;
+import java.util.function.Consumer;
 import java.util.stream.Stream;
 
 abstract class BaseMigrationStrategy implements MigrationStrategy.Instance {
@@ -50,9 +51,9 @@ Path getTypeDependentPath(String type) {
     return contextProvider.getBaseDirectory().toPath().resolve("repositories").resolve(type);
   }
 
-  Stream<Path> listSourceDirectory(Path sourceDirectory) {
-    try {
-      return Files.list(sourceDirectory);
+  void listSourceDirectory(Path sourceDirectory, Consumer<Stream<Path>> pathConsumer) {
+    try (Stream<Path> paths = Files.list(sourceDirectory)) {
+      pathConsumer.accept(paths);
     } catch (IOException e) {
       throw new UpdateException("could not read original directory", e);
     }
diff --git a/scm-webapp/src/main/java/sonia/scm/update/repository/CopyMigrationStrategy.java b/scm-webapp/src/main/java/sonia/scm/update/repository/CopyMigrationStrategy.java
index 0032238729..9702677513 100644
--- a/scm-webapp/src/main/java/sonia/scm/update/repository/CopyMigrationStrategy.java
+++ b/scm-webapp/src/main/java/sonia/scm/update/repository/CopyMigrationStrategy.java
@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.update.repository;
 
 import org.slf4j.Logger;
@@ -62,15 +62,17 @@ public Optional<Path> migrate(String id, String name, String type) {
 
   private void copyData(Path sourceDirectory, Path targetDirectory) {
     createDataDirectory(targetDirectory);
-    listSourceDirectory(sourceDirectory).forEach(
+    listSourceDirectory(sourceDirectory, paths -> paths.forEach(
       sourceFile -> {
         Path targetFile = targetDirectory.resolve(sourceFile.getFileName());
         if (Files.isDirectory(sourceFile)) {
+          LOG.trace("traversing down into sub directory {}", sourceFile);
           copyData(sourceFile, targetFile);
         } else {
+          LOG.trace("copying file {} to {}", sourceFile, targetFile);
           copyFile(sourceFile, targetFile);
         }
       }
-    );
+    ));
   }
 }
diff --git a/scm-webapp/src/main/java/sonia/scm/update/repository/InlineMigrationStrategy.java b/scm-webapp/src/main/java/sonia/scm/update/repository/InlineMigrationStrategy.java
index 4d8a2a987f..6c5d7afeed 100644
--- a/scm-webapp/src/main/java/sonia/scm/update/repository/InlineMigrationStrategy.java
+++ b/scm-webapp/src/main/java/sonia/scm/update/repository/InlineMigrationStrategy.java
@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.update.repository;
 
 import org.slf4j.Logger;
@@ -67,20 +67,23 @@ private void moveData(Path sourceDirectory, Path targetDirectory) {
 
   private void moveData(Path sourceDirectory, Path targetDirectory, boolean deleteDirectory) {
     createDataDirectory(targetDirectory);
-    listSourceDirectory(sourceDirectory)
+    listSourceDirectory(sourceDirectory, paths -> paths
       .filter(sourceFile -> !targetDirectory.equals(sourceFile))
       .forEach(
         sourceFile -> {
           Path targetFile = targetDirectory.resolve(sourceFile.getFileName());
           if (Files.isDirectory(sourceFile)) {
+            LOG.trace("traversing down into sub directory {}", sourceFile);
             moveData(sourceFile, targetFile, true);
           } else {
+            LOG.trace("moving file {} to {}", sourceFile, targetFile);
             moveFile(sourceFile, targetFile);
           }
         }
-      );
+      ));
     if (deleteDirectory) {
       try {
+        LOG.trace("deleting source directory {}", sourceDirectory);
         Files.delete(sourceDirectory);
       } catch (IOException e) {
         LOG.warn("could not delete source repository directory {}", sourceDirectory);
diff --git a/scm-webapp/src/main/java/sonia/scm/update/repository/MoveMigrationStrategy.java b/scm-webapp/src/main/java/sonia/scm/update/repository/MoveMigrationStrategy.java
index 08b859481d..c5115a0637 100644
--- a/scm-webapp/src/main/java/sonia/scm/update/repository/MoveMigrationStrategy.java
+++ b/scm-webapp/src/main/java/sonia/scm/update/repository/MoveMigrationStrategy.java
@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.update.repository;
 
 import org.slf4j.Logger;
@@ -83,17 +83,20 @@ private void delete(Path rootPath, List<String> directories) {
 
   private void moveData(Path sourceDirectory, Path targetDirectory) {
     createDataDirectory(targetDirectory);
-    listSourceDirectory(sourceDirectory).forEach(
+    listSourceDirectory(sourceDirectory, paths -> paths.forEach(
       sourceFile -> {
         Path targetFile = targetDirectory.resolve(sourceFile.getFileName());
         if (Files.isDirectory(sourceFile)) {
+          LOG.trace("traversing down into sub directory {}", sourceFile);
           moveData(sourceFile, targetFile);
         } else {
+          LOG.trace("moving file {} to {}", sourceFile, targetFile);
           moveFile(sourceFile, targetFile);
         }
       }
-    );
+    ));
     try {
+      LOG.trace("deleting source directory {}", sourceDirectory);
       Files.delete(sourceDirectory);
     } catch (IOException e) {
       LOG.warn("could not delete source repository directory {}", sourceDirectory);