software raid doesn't assemble before mount on boot

[Stephan Fabel]

I've configured a Software RAID5 using three hard drives and mdadm. The RAID works, I can access the data, however for some reason it does not "assemble" on boot, and the automount subsequently fails with and error message offering me to Ignore or Skip the mounting process. Turns out that after booting, the device /dev/md0 does not exist on my system.

I've configured /etc/mdadm/mdadm.conf (attached), ran "mdadm -As /dev/md0" as suggested by various guides around the web and added raid456 to /etc/modules in the hopes that this would somehow make it work but to no avail.

In my /etc/fstab I'm not refering to the RAID as /dev/md0, but instead use the UUID of md0.

My workaround currently is this:

Once I login, I can issue

# mdadm --assemble --scan

and it creates my /dev/md0 which is then accessible and works without a problem.

[Stephan Fabel (sfabel)]

Missing info:

%lsb_release -rd
Description: Ubuntu 11.10
Release: 11.10

~%apt-cache policy mdadm
mdadm:
  Installed: 3.1.4-1+8efb9d1ubuntu6
  Candidate: 3.1.4-1+8efb9d1ubuntu6
  Version table:
 *** 3.1.4-1+8efb9d1ubuntu6 0
        500 http://mirror.coe.hawaii.edu/ubuntu/ oneiric/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu/ oneiric/main amd64 Packages
        100 /var/lib/dpkg/status

~%uname -r
3.0.0-16-generic