diff --git a/src/applications/files/management/PhabricatorFilesManagementMigrateWorkflow.php b/src/applications/files/management/PhabricatorFilesManagementMigrateWorkflow.php
index 83978d9764..eda43e2ef3 100644
--- a/src/applications/files/management/PhabricatorFilesManagementMigrateWorkflow.php
+++ b/src/applications/files/management/PhabricatorFilesManagementMigrateWorkflow.php
@@ -36,6 +36,12 @@ final class PhabricatorFilesManagementMigrateWorkflow
             'name'      => 'all',
             'help'      => pht('Migrate all files.'),
           ),
+          array(
+            'name' => 'copy',
+            'help' => pht(
+              'Copy file data instead of moving it: after migrating, do not '.
+              'remove the old data even if it is no longer referenced.'),
+          ),
           array(
             'name'      => 'names',
             'wildcard'  => true,
@@ -70,6 +76,8 @@ final class PhabricatorFilesManagementMigrateWorkflow
     $min_size = (int)$args->getArg('min-size');
     $max_size = (int)$args->getArg('max-size');
 
+    $is_copy = $args->getArg('copy');
+
     $failed = array();
     $engines = PhabricatorFileStorageEngine::loadAllEngines();
     $total_bytes = 0;
@@ -158,7 +166,7 @@ final class PhabricatorFilesManagementMigrateWorkflow
         if ($is_dry_run) {
           // Do nothing, this is a dry run.
         } else {
-          $file->migrateToEngine($target_engine);
+          $file->migrateToEngine($target_engine, $is_copy);
         }
 
         $total_files += 1;
diff --git a/src/applications/files/storage/PhabricatorFile.php b/src/applications/files/storage/PhabricatorFile.php
index 8d81c3ae98..d301abceca 100644
--- a/src/applications/files/storage/PhabricatorFile.php
+++ b/src/applications/files/storage/PhabricatorFile.php
@@ -422,7 +422,10 @@ final class PhabricatorFile extends PhabricatorFileDAO
     return self::buildFromFileData($data, $params);
   }
 
-  public function migrateToEngine(PhabricatorFileStorageEngine $engine) {
+  public function migrateToEngine(
+    PhabricatorFileStorageEngine $engine,
+    $make_copy) {
+
     if (!$this->getID() || !$this->getStorageHandle()) {
       throw new Exception(
         pht("You can not migrate a file which hasn't yet been saved."));
@@ -446,10 +449,12 @@ final class PhabricatorFile extends PhabricatorFileDAO
     $this->setStorageHandle($new_handle);
     $this->save();
 
-    $this->deleteFileDataIfUnused(
-      $old_engine,
-      $old_identifier,
-      $old_handle);
+    if (!$make_copy) {
+      $this->deleteFileDataIfUnused(
+        $old_engine,
+        $old_identifier,
+        $old_handle);
+    }
 
     return $this;
   }