I installed a new disk and am trying to create a one disk raid 1 on it (and will add the second disk later)
(Debian testing compiled with raid built into kernel) $ cat /proc/mdstat Personalities : [linear] [raid1] [raid10] [multipath] [faulty] [raid6] [raid5] [raid4] unused devices: <none> I have two partions on /dev/sda $sudo fdisk -l /dev/sda Disk /dev/sda: 400.0 GB, 400088457216 bytes 255 heads, 63 sectors/track, 48641 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x8b148706 Device Boot Start End Blocks Id System /dev/sda1 1 30 240943+ fd Linux raid autodetect /dev/sda2 31 517 3911827+ 82 Linux swap / Solaris /dev/sda3 518 48641 386556030 fd Linux raid autodetect but when I run mdadm I get the followng: $ sudo mdadm --create /dev/md0 --level=raid1 --raid-devices=2 /dev/sda3 missing mdadm: /dev/sda3 is too small: 0K mdadm: create aborted any help wil be appreciated. Thanks Stuart