[Bug 136252] Re: [->UUIDudev] mdadm.conf w/o ARRAY lines but udev/mdadm not assembling arrays. (boot & hotplug fails)

[Ben Bucksch]

Again I ran into this. System was an Ubuntu 8.10 with an 8-disk md array plus separate system disk. Given that 8.10 is not supported anymore, I needed to upgrade to 10.04. All I did was change sources.list to lucid and apt-get dist-upgrade, reboot, and I am left without my array.
* mdadm.conf is the default, no ARRAY line
* mdadm --auto-detect does nothing
* mdadm --assemble /dem/md0 complains
Worse,
* Adding ARRAY /dev/md0 devices=/dev/sda,/dev/sdb,/dev/sdc,/dev/sdd,/dev/sde,/dev/sdf,/dev/sdg,/dev/sdh to mdadm.conf and doing mdadm --assemble /dem/md0 says that /dev/sdb has no superblock - which is freaky, given that it worked fine before the upgrade.

So, this is still breaking systems, even when upgrading to the latest
10.04 LTS.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to mdadm in Ubuntu.
https://bugs.launchpad.net/bugs/136252

Title:
  [->UUIDudev]  mdadm.conf w/o ARRAY lines but udev/mdadm not assembling
  arrays. (boot & hotplug fails)

Status in “mdadm” package in Ubuntu:
  In Progress

Bug description:
  Binary package hint: mdadm

  Hi,

  I could not boot from my /dev/md1 -> /dev/vg01/lv_root partition,
  because the initrd could not assemble the md0 and md1 devices. After
  reading mdadm.conf, I added these two lines to my config:

  # definitions of existing MD arrays
  ARRAY /dev/md0 devices=/dev/sda1,/dev/sdb1
  ARRAY /dev/md1 devices=/dev/sda5,/dev/sdb5

  and updated initramfs. After this, the system started normally. Before
  figuring out this, I used dpkg-reconfigure mdadm. So this seems to
  produce a non working config, which is copied to the initrd.

  Kind regards

  Christian

  -> However on hotplug systems mdadm.conf should not have to contain
  any references to specific DEVICEs, ARRAYs or HOMEHOST.

  -> We need to switch to a pure and secure UUID-based raid assembly.
  The boot up scripts already support and use UUIDs, but mdadm needs to
  be convinced (-> comment #42)