diff --git a/src/views/app.html b/src/views/app.html
index 81213ee8c..a2dd0fc60 100644
--- a/src/views/app.html
+++ b/src/views/app.html
@@ -822,7 +822,7 @@
                 <span class="caret"></span>
               </button>
               <ul class="dropdown-menu">
-                <li><a href="" ng-click="graphs.setPeriod(6, '6 hours')">6 hours</a></li>
+                <li><a href="" ng-click="graphs.setPeriod(12, '12 hours')">12 hours</a></li>
                 <li><a href="" ng-click="graphs.setPeriod(24, '24 hours')">24 hours</a></li>
                 <li><a href="" ng-click="graphs.setPeriod(24*7, '7 days')">7 days</a></li>
                 <li><a href="" ng-click="graphs.setPeriod(24*30, '30 days')">30 days</a></li>
diff --git a/src/views/app.js b/src/views/app.js
index 17d1a2ace..e2eef5543 100644
--- a/src/views/app.js
+++ b/src/views/app.js
@@ -593,8 +593,8 @@ angular.module('Application').controller('AppController', ['$scope', '$location'
     $scope.graphs = {
         error: {},
 
-        period: 6,
-        periodLabel: '6 hours',
+        period: 12, // set as 12 because disk graphs is only collected twice a day
+        periodLabel: '12 hours',
         memoryChart: null,
         diskChart: null,