diff --git a/mapfile.c b/mapfile.c
index 1c2dc52..6169d52 100644
--- a/mapfile.c
+++ b/mapfile.c
@@ -245,3 +245,18 @@ struct map_ent *map_by_devnum(struct map_ent **map, int devnum)
 			return mp;
 	return NULL;
 }
+
+struct map_ent *map_by_name(struct map_ent **map, char *name)
+{
+	struct map_ent *mp;
+	if (!*map)
+		map_read(map);
+
+	for (mp = *map ; mp ; mp = mp->next) {
+		if (strncmp(mp->path, "/dev/md/", 8) != 0)
+			continue;
+		if (strcmp(mp->path+8, name) == 0)
+			return mp;
+	}
+	return NULL;
+}
diff --git a/mdadm.h b/mdadm.h
index 8131b60..af0f9e8 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -320,7 +320,8 @@ struct map_ent {
 extern int map_update(struct map_ent **mpp, int devnum, char *metadata,
 		      int uuid[4], char *path);
 extern struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4]);
-struct map_ent *map_by_devnum(struct map_ent **map, int devnum);
+extern struct map_ent *map_by_devnum(struct map_ent **map, int devnum);
+extern struct map_ent *map_by_name(struct map_ent **map, char *name);
 extern void map_read(struct map_ent **melp);
 extern int map_write(struct map_ent *mel);
 extern void map_delete(struct map_ent **mapp, int devnum);
diff --git a/mdassemble.c b/mdassemble.c
index 02afc2d..a680378 100644
--- a/mdassemble.c
+++ b/mdassemble.c
@@ -84,6 +84,10 @@ int map_update(struct map_ent **mpp, int devnum, char *metadata,
 {
 	return 0;
 }
+struct map_ent *map_by_name(struct map_ent **mpp, char *name)
+{
+	return NULL;
+}
 
 int rv;
 int mdfd = -1;
diff --git a/mdopen.c b/mdopen.c
index 44efb84..32ccdbb 100644
--- a/mdopen.c
+++ b/mdopen.c
@@ -269,19 +269,33 @@ int create_mddev(char *dev, char *name, int autof, int trustworthy,
 		 * reasonable length and remove '/'
 		 */
 		char *cp;
+		struct map_ent *map = NULL;
+		int conflict = 1;
+		int unum = 0;
+		int cnlen;
 		strncpy(cname, name, 200);
 		cname[200] = 0;
 		while ((cp = strchr(cname, '/')) != NULL)
 			*cp = '-';
-		if (trustworthy == METADATA)
-			/* always add device number to metadata */
-			sprintf(cname+strlen(cname), "%d", num);
-		else if (trustworthy == FOREIGN &&
-			 strchr(cname, ':') == NULL)
-			/* add _%d to FOREIGN array that don't have
-			 * a 'host:' prefix
-			 */
-			sprintf(cname+strlen(cname), "_%d", num<0?(-1-num):num);
+		if (trustworthy == LOCAL ||
+		    (trustworthy == FOREIGN && strchr(cname, ':') != NULL)) {
+			/* Only need suffix if there is a conflict */
+			if (map_by_name(&map, cname) == NULL)
+				conflict = 0;
+		}
+		cnlen = strlen(cname);
+		while (conflict) {
+			if (trustworthy == METADATA)
+				sprintf(cname+cnlen, "%d", unum);
+			else
+				/* add _%d to FOREIGN array that don't 
+				 * a 'host:' prefix
+				 */
+				sprintf(cname+cnlen, "_%d", unum);
+			unum++;
+			if (map_by_name(&map, cname) == NULL)
+				conflict = 0;
+		}
 	}
 	if (cname[0] == 0)
 		strcpy(chosen, devname);