diff -uNr xen-3.4.3.orig/tools/ioemu-qemu-xen/xenstore.c xen-3.4.3/tools/ioemu-qemu-xen/xenstore.c
--- xen-3.4.3.orig/tools/ioemu-qemu-xen/xenstore.c	2010-04-14 16:34:59.000000000 +0200
+++ xen-3.4.3/tools/ioemu-qemu-xen/xenstore.c	2011-11-23 15:17:56.929696307 +0100
@@ -453,6 +453,15 @@
             params = newparams;
 	    format = &bdrv_raw;
         }
+	/* handle drbd mapping */
+	if (!strcmp(drv, "drbd")) {
+	    char *newparams = malloc(17 + strlen(params) + 1);
+	    sprintf(newparams, "/dev/drbd/by-res/%s", params);
+	    free(params);
+	    sleep(10);
+	    params = newparams;
+	    format = &bdrv_raw;
+	} 
 
 #if 0
 	/* Phantom VBDs are disabled because the use of paths