[Bug 541058] Re: [->UUIDudev] mdadm fails to automatically assemble raid during boot (without mdadm.conf)

[rooijan]

For me no amount of settings in mdadm.conf worked.  --examine looks fine
on both my partitions participating in a raid 1 volume.

I played with DEVICE, HOMEHOST, ARRAY and tried all kind of suggestions.
The only way I could get my raid1 array to assemble on bootup was doing
this:

root at jamaica:~# cat /lib/udev/rules.d/85-mdadm.rules | grep mdadm
# This file causes block devices with Linux RAID (mdadm) signatures to
# automatically cause mdadm to be run.
	RUN+="/sbin/mdadm /dev/md0 --assemble --add /dev/sdb2 /dev/sdc2"
	#RUN+="/sbin/mdadm --incremental $env{DEVNAME}"

Plus:
root at jamaica:~# update-initramfs -u

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https://bugs.launchpad.net/bugs/541058

Title:
  [->UUIDudev] mdadm fails to automatically assemble raid during boot
  (without mdadm.conf)

Status in “mdadm” package in Ubuntu:
  In Progress

Bug description:
  Binary package hint: mdadm

  Creating an mdadm array works fine:
  mdadm --create /dev/md0 -n 3 -l5 /dev/sdb1 /dev/sdc1 /dev/sdd1
  Now when booting the array is assembled correctly.

  Delete the array and zero-superblock, create new partition and mark as "fd", create the same array again with command above.
  Now the system tries to assemble a single device into /dev/md_d0 - when other devices are missing.

  I checked each device with -examine and each reports the same uuid, the same host and the same name.
  In order to get it working one has to stop the md_d0 and assemble manually:
  mdadm --stop /dev/md_d0
  mdadm --assemble /dev/md0 /dev/sdb1 /dev/sdc1 /dev/sdd1

  To overcome this problem one has to remove the homehost from mdadm.conf and assemble the array manually during boot.
  What helps ist to reinstall the system ...

  This bug is pretty often found when googling around. Possible hints
  are udev and dmraid, whereas I already deinstalled dmraid but didn't
  help.

  Ubuntu 9.10 Linux 2.6.31-14-generic-pae
  mdadm 2.6.7.1

  * The array gets configured when mdadm.conf reflects the array
  definitions. But it does not get assembled automatically

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