References: bnc#892003
For very large memory VMs Xen takes a long time scrubbing memory
which causes the libvirt connection to timeout. Upstream was not
interested in making this a preferences option (4/11/2015)
Index: virt-manager-1.2.1/virtManager/connection.py
===================================================================
--- virt-manager-1.2.1.orig/virtManager/connection.py
+++ virt-manager-1.2.1/virtManager/connection.py
@@ -906,7 +906,7 @@ class vmmConnection(vmmGObject):
         self.caps.get_cpu_values("x86_64")
 
         try:
-            self._backend.setKeepAlive(20, 1)
+            self._backend.setKeepAlive(20, 10)
         except Exception, e:
             if (type(e) is not AttributeError and
                 not util.is_error_nosupport(e)):