FYI, with both mdadm ver 2.4.1 and 2.5.2 I can't mdadm --create with a ver1 superblock and a write intent bitmap on x86_64. running: mdadm --create /dev/md2 -e 1.0 -l 1 --bitmap=internal -n 2 /dev/sdd --write-mostly /dev/nbd2 I get: mdadm: RUN_ARRAY failed: Invalid argument Mike - 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