diff --git a/core/lib/Drupal/Core/Config/DatabaseStorage.php b/core/lib/Drupal/Core/Config/DatabaseStorage.php
index 162fd46..1dd8507 100644
--- a/core/lib/Drupal/Core/Config/DatabaseStorage.php
+++ b/core/lib/Drupal/Core/Config/DatabaseStorage.php
@@ -18,7 +18,8 @@ class DatabaseStorage implements StorageInterface {
   /**
    * Database connection options for this storage controller.
    *
-   * - target: The connection to use for storage operations.
+   * - connection: The connection key to use.
+   * - target: The target on the connection to use.
    *
    * @var array
    */
@@ -29,6 +30,7 @@ class DatabaseStorage implements StorageInterface {
    */
   public function __construct(array $options = array()) {
     $options += array(
+      'connection' => 'default',
       'target' => 'default',
     );
     $this->options = $options;
@@ -38,7 +40,7 @@ class DatabaseStorage implements StorageInterface {
    * Returns the database connection to use.
    */
   protected function getConnection() {
-    return Database::getConnection($this->options['target']);
+    return Database::getConnection($this->options['target'], $this->options['connection']);
   }
 
   /**
@@ -71,6 +73,8 @@ class DatabaseStorage implements StorageInterface {
    * Implements Drupal\Core\Config\StorageInterface::write().
    *
    * @throws PDOException
+   *
+   * @todo Ignore slave targets for data manipulation operations.
    */
   public function write($name, array $data) {
     $data = $this->encode($data);
@@ -85,6 +89,8 @@ class DatabaseStorage implements StorageInterface {
    * Implements Drupal\Core\Config\StorageInterface::delete().
    *
    * @throws PDOException
+   *
+   * @todo Ignore slave targets for data manipulation operations.
    */
   public function delete($name) {
     $options = array('return' => Database::RETURN_AFFECTED) + $this->options;
diff --git a/core/lib/Drupal/Core/Config/FileStorage.php b/core/lib/Drupal/Core/Config/FileStorage.php
index cee29ae..7827dc0 100644
--- a/core/lib/Drupal/Core/Config/FileStorage.php
+++ b/core/lib/Drupal/Core/Config/FileStorage.php
@@ -94,7 +94,7 @@ class FileStorage implements StorageInterface {
    */
   public function write($name, array $data) {
     $data = $this->encode($data);
-    $status = file_put_contents($this->getFilePath($name), $data);
+    $status = @file_put_contents($this->getFilePath($name), $data);
     if ($status === FALSE) {
       throw new StorageException('Failed to write configuration file: ' . $this->getFilePath($name));
     }
@@ -106,6 +106,9 @@ class FileStorage implements StorageInterface {
    */
   public function delete($name) {
     if (!$this->exists($name)) {
+      if (!file_exists($this->options['directory'])) {
+        throw new StorageException($this->options['directory'] . '/ not found.');
+      }
       return FALSE;
     }
     return drupal_unlink($this->getFilePath($name));
@@ -138,11 +141,13 @@ class FileStorage implements StorageInterface {
    * Implements Drupal\Core\Config\StorageInterface::listAll().
    */
   public function listAll($prefix = '') {
+    // glob() silently ignores the error of a non-existing search directory,
+    // even with the GLOB_ERR flag.
+    if (!file_exists($this->options['directory'])) {
+      throw new StorageException($this->options['directory'] . '/ not found.');
+    }
     $extension = '.' . self::getFileExtension();
     $files = glob($this->options['directory'] . '/' . $prefix . '*' . $extension);
-    if ($files === FALSE) {
-      return array();
-    }
     $clean_name = function ($value) use ($extension) {
       return basename($value, $extension);
     };
diff --git a/core/lib/Drupal/Core/DependencyInjection/ContainerBuilder.php b/core/lib/Drupal/Core/DependencyInjection/ContainerBuilder.php
index 98a9bd3..b811199 100644
--- a/core/lib/Drupal/Core/DependencyInjection/ContainerBuilder.php
+++ b/core/lib/Drupal/Core/DependencyInjection/ContainerBuilder.php
@@ -33,6 +33,7 @@ class ContainerBuilder extends BaseContainerBuilder {
     // Register configuration storage dispatcher.
     $this->setParameter('config.storage.info', array(
       'Drupal\Core\Config\DatabaseStorage' => array(
+        'connection' => 'default',
         'target' => 'default',
         'read' => TRUE,
         'write' => TRUE,
diff --git a/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
index 15ccb90..3e6b254 100644
--- a/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
+++ b/core/modules/config/lib/Drupal/config/Tests/Storage/ConfigStorageTestBase.php
@@ -86,7 +86,8 @@ abstract class ConfigStorageTestBase extends WebTestBase {
       $this->fail('Exception not thrown upon writing to a non-existing storage bin.');
     }
     catch (\Exception $e) {
-      $this->pass('Exception thrown upon writing to a non-existing storage bin.');
+      $class = get_class($e);
+      $this->pass($class . ' thrown upon writing to a non-existing storage bin.');
     }
 
     // Deleting from a non-existing storage bin throws an exception.
@@ -95,7 +96,8 @@ abstract class ConfigStorageTestBase extends WebTestBase {
       $this->fail('Exception not thrown upon deleting from a non-existing storage bin.');
     }
     catch (\Exception $e) {
-      $this->pass('Exception thrown upon deleting from a non-existing storage bin.');
+      $class = get_class($e);
+      $this->pass($class . ' thrown upon deleting from a non-existing storage bin.');
     }
 
     // Listing on a non-existing storage bin throws an exception.
@@ -104,7 +106,8 @@ abstract class ConfigStorageTestBase extends WebTestBase {
       $this->fail('Exception not thrown upon listing from a non-existing storage bin.');
     }
     catch (\Exception $e) {
-      $this->pass('Exception thrown upon listing from a non-existing storage bin.');
+      $class = get_class($e);
+      $this->pass($class . ' thrown upon listing from a non-existing storage bin.');
     }
   }
 
diff --git a/core/modules/config/lib/Drupal/config/Tests/Storage/DatabaseStorageTest.php b/core/modules/config/lib/Drupal/config/Tests/Storage/DatabaseStorageTest.php
index 6fa1094..2e1599f 100644
--- a/core/modules/config/lib/Drupal/config/Tests/Storage/DatabaseStorageTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/Storage/DatabaseStorageTest.php
@@ -24,7 +24,7 @@ class DatabaseStorageTest extends ConfigStorageTestBase {
   function setUp() {
     parent::setUp();
     $this->storage = new DatabaseStorage();
-    $this->invalidStorage = new DatabaseStorage(array('target' => 'invalid'));
+    $this->invalidStorage = new DatabaseStorage(array('connection' => 'invalid'));
   }
 
   protected function read($name) {