diff --git a/www/admin/inner.js b/www/admin/inner.js
index 4f7f0f50f..282e22088 100644
--- a/www/admin/inner.js
+++ b/www/admin/inner.js
@@ -2091,11 +2091,16 @@ Example
         onRefreshStats.reg(onRefresh);
         return $div;
     };
+
+    Messages.admin_diskUsageWarning = "Depending on the size of the data stored on your instance, generating this report can consume all the memory available on your server and lead to a crash. Use with caution!"; // XXX
     create['disk-usage'] = function () {
         var key = 'disk-usage';
         var $div = makeBlock(key, true); // Msg.admin_diskUsageHint, .admin_diskUsageTitle, .admin_diskUsageButton
         var called = false;
+
         $div.find('button').click(function () {
+        UI.confirm(Messages.admin_diskUsageWarning, function (yes) {
+            if (!yes) { return; }
             $div.find('button').hide();
             if (called) { return; }
             called = true;
@@ -2125,6 +2130,8 @@ Example
                 })));
             });
         });
+        });
+
         return $div;
     };