Hi Neil, Creation of a native raid fails: mdadm -CR /dev/md/aaa -n 2 -l 1 /dev/sdb /dev/sdc mdadm: ADD_NEW_DISK for /dev/sdb failed: Invalid argument. In /var/log/messages: md: sdb does not have a valid v1.2 superblock, not importing! This on top on devel-3.2. The bug is probably connected with fix 1cc7f4feb9a979 "Don't close fds in write_init_super". In the call to get_dev_size from write_init_super1 the di->fd descriptor is zero and get_dev_size returns with error. One of the first steps in load_super1 is call free_super1(st). free_super1 releases st->info pointer and closes(di->fd); The sequence in write_init_super1: for (di = st->info; di && ! rv ; di = di->next) { .... 1060 if (load_super1(&refst, di->fd, NULL)==0) { 1076 <..cut..> 1077 if (!get_dev_size(di->fd, NULL, &dsize)) 1078 return 1; < ...cut ... > } Thanks, Marcin Labun -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html