Add note in admin guide about drbd stacked devices

Fixes: http://code.google.com/p/ganeti/issues/detail?id=251
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

diff --git a/doc/admin.rst b/doc/admin.rst
index 80028e6..d7f70f5 100644 (file)
--- a/doc/admin.rst
+++ b/doc/admin.rst
@@ -138,6 +138,10 @@ drbd
   to obtain a highly available instance that can be failed over to a
   remote node should the primary one fail.
 
+  .. note:: Ganeti does not support DRBD stacked devices:
+     DRBD stacked setup is not fully symmetric and as such it is
+     not working with live migration.
+
 rbd
   The instance will use Volumes inside a RADOS cluster as backend for its
   disks. It will access them using the RADOS block device (RBD).