Comment 4 for bug 1022915

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: <none>