diff --git a/src/Config.php b/src/Config.php
index e853d19..28cedf4 100644
--- a/src/Config.php
+++ b/src/Config.php
@@ -246,11 +246,13 @@ Class Config {
    */
   public static function ini_set($option, $value) {
     Log :: trace('Set PHP INI option "%s" to "%s"', $option, $value);
-    if (ini_set($option, $value) === false)
+    // ini_set() return the old value in case of success or false in case of error. If option is
+    // unset, ini_set() will also return false. To detect error, compare set value with value
+    // retrieve after using ini_get().
+    ini_set($option, $value);
+    $new_value = ini_get($option);
+    if ($new_value !== $value)
       Log::warning('Fail to set PHP INI option "%s" to "%s"', $option, $value);
-    Log :: trace(
-      'PHP INI option "%s" after setting it to "%s": "%s"',
-      $option, $value, vardump(ini_get($option)));
   }
 
 }