Trouble with raid and lvm on Ubuntu Dapper

I am not sure why and how, but I fixed it :-)

• I use software raid (mdadm) and do NOT use lvm (but lvm is installed automatically with Ubuntu Dapper Server Edition).
• I have an mdadm.conf file like this:
  # cat mdadm/mdadm.conf ARRAY /dev/md7 level=raid1 num-devices=2 UUID=cada920:4eca7627:5412f973:b46b1baa ARRAY /dev/md6 level=raid1 num-devices=2 UUID=8f380fb:d10815fd:be8db44d:e572eaf7 ARRAY /dev/md8 level=raid1 num-devices=2 UUID=59808df:2a081aeb:3e212539:9766f1e0 ARRAY /dev/md5 level=raid1 num-devices=2 UUID=ecdcf44:c83a999a:afab4c83:46c1829a ARRAY /dev/md2 level=raid1 num-devices=2 UUID=5c6a4dd:999cbc80:ac49c25d:4c2489b8 ARRAY /dev/md1 level=raid1 num-devices=2 UUID=d07eae6:e4c76e60:371344cd:17049a8e ARRAY /dev/md0 level=raid1 num-devices=2 UUID=ae444d6:d69a6c47:6a3532a6:2386ac95 DEVICE /dev/hda* /dev/hdc*
• After booting, md0, md1, and md2 are created and mounted perfectly. However, two extra devices are created (and not mounted because they are not in fstab): md3 and md4.
• with cat /proc/mdstat. the device 5 - 8 are created in a strange way:
  md8 : active raid1 dm-3[1] dm-2[0] 70356544 blocks [2/2] [UU] md7 : active raid1 dm-1[1] dm-0[0] 9767424 blocks [2/2] [UU] md6 : active raid1 hdc8[0] hda8[1] 70356544 blocks [2/2] [UU] md5 : active raid1 hdc7[0] hda7[1] 9767424 blocks [2/2] [UU]
  So, md8 and md6 are equal; so is md5 and md7. Please note that the devices of md5 and md6 are hda/hdc as it should; but md7 and md8 are using 'dm-1, dm-0, dm-3 and dm-2' which is strange (to me).
• I disabled the lvm boot script in /etc/init.d, but to no avail.
• after stopping /dev/md3 - /dev/md8, and then assembling them again using
  mdadm --assemble --scan
  the devices where created as should:
  md8 : active raid1 hdc8[0] hda8[1] 70356544 blocks [2/2] [UU] md7 : active raid1 hdc7[0] hda7[1] 9767424 blocks [2/2] [UU] md6 : active raid1 hdc6[0] hda6[1] 48829440 blocks [2/2] [UU] md5 : active raid1 hda5[0] hdc5[1] 5855552 blocks [2/2] [UU]
• after the next boot, everyting was a mess again, but md3 and md4 where created (altough they are not in mdadm.conf !)
• I modified mdadm.conf and fstab, to now use devices md3 - md6 instead of md5 - md8
• after next reboot, all was fine, and no weird 'dm' devices where created anymore.

I don't know why or how, like I said, but it seems to me it's a bug because the startup scripts don't seem to follow what is in /etc/mdadm.conf

Thanks too Frogzoo at #ubuntu for thinking together with me.

See also: https://wiki.ubuntu.com/UdevLvmMdadmEvmsAgain