root@imap:~# apt-get install mdadm/precise-proposed Reading package lists... Done Building dependency tree Reading state information... Done Selected version '3.2.5-1ubuntu0.1' (Ubuntu:12.04/precise-proposed [amd64]) for 'mdadm' The following packages were automatically installed and are no longer required: libcrypt-openssl-random-perl libcrypt-passwdmd5-perl Use 'apt-get autoremove' to remove them. The following packages will be DOWNGRADED: mdadm 0 upgraded, 0 newly installed, 1 downgraded, 0 to remove and 28 not upgraded. Need to get 520 kB of archives. After this operation, 1,024 B disk space will be freed. Do you want to continue [Y/n]? y Get:1 http://archive.ubuntu.com/ubuntu/ precise-proposed/main mdadm amd64 3.2.5-1ubuntu0.1 [520 kB] Fetched 520 kB in 1s (416 kB/s) Preconfiguring packages ... dpkg: warning: downgrading mdadm from 3.2.5-1ubuntu2 to 3.2.5-1ubuntu0.1. (Reading database ... 63219 files and directories currently installed.) Preparing to replace mdadm 3.2.5-1ubuntu2 (using .../mdadm_3.2.5-1ubuntu0.1_amd64.deb) ... * Stopping MD monitoring service mdadm --monitor ...done. Unpacking replacement mdadm ... Processing triggers for man-db ... Processing triggers for ureadahead ... ureadahead will be reprofiled on next reboot Setting up mdadm (3.2.5-1ubuntu0.1) ... Installing new version of config file /etc/logcheck/ignore.d.server/mdadm ... Removing any system startup links for /etc/init.d/mdadm-raid ... update-initramfs: deferring update (trigger activated) * Starting MD monitoring service mdadm --monitor ...done. Processing triggers for initramfs-tools ... update-initramfs: Generating /boot/initrd.img-3.2.0-27-generic localepurge: Disk space freed in /usr/share/locale: 0 KiB localepurge: Disk space freed in /usr/share/man: 0 KiB localepurge: Disk space freed in /usr/share/gnome/help: 0 KiB localepurge: Disk space freed in /usr/share/omf: 0 KiB Total disk space freed by localepurge: 0 KiB root@imap:~# mdadm -V mdadm - v3.2.5 - 18th May 2012 root@imap:~# dpkg -l|grep mdadm ii mdadm 3.2.5-1ubuntu0.1 tool to administer Linux MD arrays (software RAID) root@imap:~# apt-show-versions |grep mdadm mdadm/precise-proposed uptodate 3.2.5-1ubuntu0.1 root@imap:~# dd if=/dev/zero of=/tmp/left bs=1M count=16 16+0 records in 16+0 records out 16777216 bytes (17 MB) copied, 0.0173897 s, 965 MB/s root@imap:~# dd if=/dev/zero of=/tmp/right bs=1M count=16 16+0 records in 16+0 records out 16777216 bytes (17 MB) copied, 0.0171915 s, 976 MB/s root@imap:~# losetup /dev/loop0 /tmp/left root@imap:~# losetup /dev/loop1 /tmp/right root@imap:~# mdadm --create /dev/md/test -l 1 -n 2 /dev/loop0 /dev/loop1 mdadm: Note: this array has metadata at the start and may not be suitable as a boot device. If you plan to store '/boot' on this device please ensure that your boot-loader understands md/v1.x metadata, or use --metadata=0.90 Continue creating array? y mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md/test started. root@imap:~# mdadm -G /dev/md/test -b internal root@imap:~# cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md127 : active raid1 loop1[1] loop0[0] 16320 blocks super 1.2 [2/2] [UU] bitmap: 0/1 pages [0KB], 65536KB chunk md1 : active raid1 sda2[0] sdb2[1] 3905524 blocks super 1.2 [2/2] [UU] bitmap: 0/1 pages [0KB], 65536KB chunk md3 : active raid1 sda4[0] sdb4[1] 956904000 blocks super 1.2 [2/2] [UU] bitmap: 0/8 pages [0KB], 65536KB chunk md2 : active raid1 sda3[0] sdb3[1] 15624120 blocks super 1.2 [2/2] [UU] bitmap: 1/1 pages [4KB], 65536KB chunk md0 : active raid1 sda1[0] sdb1[1] 194548 blocks super 1.2 [2/2] [UU] bitmap: 0/1 pages [0KB], 65536KB chunk unused devices: