enable backupswitcher by default

app/UI/Disk/Forms/UpdateForm.php

@@ -56,6 +56,8 @@ class UpdateForm extends BaseForm implements ClientArea
         $backupSwitcher = $this->getField('backup');
         if ( parent::getFormData()['id'] == 'scsi0') {
             $backupSwitcher->addHtmlAttribute(':disabled', true);
+            $backupSwitcher->addHtmlAttribute(':checked', true);
+            $backupSwitcher->setValue()
         }
 
     }
@@ -77,7 +79,6 @@ class UpdateForm extends BaseForm implements ClientArea
         if ($this->configuration()->isPermissionAdditionalDiskBackup())
         {
             $field = new Switcher('backup');
-            $field->setDefaultValue('on');
             $this->addField($field);
         }
     }