diff --git a/conf/default.conf.php b/conf/default.conf.php
index 98b7d9ca7f..2d5f697122 100644
--- a/conf/default.conf.php
+++ b/conf/default.conf.php
@@ -719,6 +719,13 @@ return array(
   // fits within configured limits.
   'storage.engine-selector' => 'PhabricatorDefaultFileStorageEngineSelector',
 
+  // Phabricator puts databases in a namespace, which defualts to "phabricator"
+  // -- for instance, the Differential database is named
+  // "phabricator_differential" by default. You can change this namespace if you
+  // want. Normally, you should not do this unless you are developing
+  // Phabricator and using namespaces to separate multiple sandbox datasets.
+  'storage.default-namespace'    => 'phabricator',
+
 
 // -- Search ---------------------------------------------------------------- //
 
diff --git a/scripts/sql/manage_storage.php b/scripts/sql/manage_storage.php
index e2ed32cc02..ab547c38b5 100755
--- a/scripts/sql/manage_storage.php
+++ b/scripts/sql/manage_storage.php
@@ -40,7 +40,7 @@ $conf = PhabricatorEnv::newObjectFromConfig('mysql.configuration-provider');
 $default_user       = $conf->getUser();
 $default_password   = $conf->getPassword();
 $default_host       = $conf->getHost();
-$default_namespace  = 'phabricator';
+$default_namespace  = PhabricatorLiskDAO::getDefaultStorageNamespace();
 
 try {
   $args->parsePartial(
diff --git a/src/applications/base/storage/lisk/PhabricatorLiskDAO.php b/src/applications/base/storage/lisk/PhabricatorLiskDAO.php
index c6324fc4ff..ce978b0a34 100644
--- a/src/applications/base/storage/lisk/PhabricatorLiskDAO.php
+++ b/src/applications/base/storage/lisk/PhabricatorLiskDAO.php
@@ -23,7 +23,7 @@
 abstract class PhabricatorLiskDAO extends LiskDAO {
 
   private $edges = array();
-  private static $namespace = 'phabricator';
+  private static $namespaceStack = array();
 
 
 /* -(  Managing Edges  )----------------------------------------------------- */
@@ -65,18 +65,39 @@ abstract class PhabricatorLiskDAO extends LiskDAO {
   /**
    * @task config
    */
-  public static function setApplicationNamespace($namespace) {
-    self::$namespace = $namespace;
+  public static function pushStorageNamespace($namespace) {
+    self::$namespaceStack[] = $namespace;
   }
 
+  /**
+   * @task config
+   */
+  public static function popStorageNamespace($namespace) {
+    array_pop(self::$namespaceStack);
+  }
+
+  /**
+   * @task config
+   */
+  public static function getDefaultStorageNamespace() {
+    return PhabricatorEnv::getEnvConfig('storage.default-namespace');
+  }
 
   /**
    * @task config
    */
   public function establishLiveConnection($mode) {
+    $namespace = end(self::$namespaceStack);
+    if (!strlen($namespace)) {
+      $namespace = self::getDefaultStorageNamespace();
+    }
+    if (!strlen($namespace)) {
+      throw new Exception("No storage namespace configured!");
+    }
+
     $conf = PhabricatorEnv::newObjectFromConfig(
       'mysql.configuration-provider',
-      array($this, $mode, self::$namespace));
+      array($this, $mode, $namespace));
 
     return PhabricatorEnv::newObjectFromConfig(
       'mysql.implementation',
diff --git a/src/infrastructure/setup/storage/management/PhabricatorStorageManagementAPI.php b/src/infrastructure/setup/storage/management/PhabricatorStorageManagementAPI.php
index 2b7ea1c140..9d838a546e 100644
--- a/src/infrastructure/setup/storage/management/PhabricatorStorageManagementAPI.php
+++ b/src/infrastructure/setup/storage/management/PhabricatorStorageManagementAPI.php
@@ -25,7 +25,7 @@ final class PhabricatorStorageManagementAPI {
 
   public function setNamespace($namespace) {
     $this->namespace = $namespace;
-    PhabricatorLiskDAO::setApplicationNamespace($namespace);
+    PhabricatorLiskDAO::pushStorageNamespace($namespace);
     return $this;
   }