diff --git a/src/ceph-disk b/src/ceph-disk
index 3709dd2a863fb..52026d1dcd3dd 100755
--- a/src/ceph-disk
+++ b/src/ceph-disk
@@ -2384,7 +2384,7 @@ def parse_args():
     zap_parser.add_argument(
         'dev',
         metavar='DEV',
-        nargs='*',
+        nargs='+',
         help='path to block device',
         )
     zap_parser.set_defaults(