I just installed the latest Ubuntu 12.04 and obviously it screws something up. I'm not sure if this has anything to do with the fact that I have a Raid 1 but at the moment, I have sda and sdb which point to the same device:
# blkid /dev/sda1: UUID="88aa922a-4304-406e-8abd-edc2e9064d79" TYPE="ext2" /dev/sda2: UUID="22b881d5-6f5c-484d-94e8-e231896fa91b" TYPE="swap" /dev/sda3: UUID="e1fa161b-b014-4a6b-831a-9d8f9e04be07" TYPE="ext3" /dev/sda5: UUID="6ed19886-1cba-47b2-9ce0-7c2ea8f9c3c9" SEC_TYPE="ext2" TYPE="ext3" /dev/sdb1: UUID="88aa922a-4304-406e-8abd-edc2e9064d79" TYPE="ext2" /dev/sdb2: UUID="22b881d5-6f5c-484d-94e8-e231896fa91b" TYPE="swap" /dev/sdb3: UUID="e1fa161b-b014-4a6b-831a-9d8f9e04be07" SEC_TYPE="ext2" TYPE="ext3" /dev/sdb5: UUID="6ed19886-1cba-47b2-9ce0-7c2ea8f9c3c9" TYPE="ext3"
But I have only one "visible" hard disc, so this ought to be sda. In my earlier version (10.10) /dev/mapper took care of it. Look at the mount points below. In the current version, this doesn't work anymore, so I entered sda mount points to fstab at first, which seemed to work, but when I execute the mount command, I saw that suddendly one partition was mounted as sdb instead of sda. So I tried to use the UUID as file system in fstab but the problem still exists. Which is even worse: It mixes up both devices. That means it sometimes mount one partition as sda, at next reboot it is suddendly sdb. And it behaves as it would mount different hard drives, because my /home partition was mounted once as sda, now as sdb and changes and setting I made in file system were suddenly "reset". What can I do? Should I delete all sdb block specials?
# <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc nodev,noexec,nosuid 0 0 #/dev/mapper/pdc_ccfhbjbeeg3 / ext3 errors=remount-ro 0 1 #/dev/mapper/pdc_ccfhbjbeeg1 /boot ext2 defaults 0 2 #/dev/mapper/pdc_ccfhbjbeeg5 /home ext3 defaults 0 2 #/dev/mapper/pdc_ccfhbjbeeg2 none swap sw 0 0 #/dev/sda1 /boot ext2 defaults 0 2 #/dev/sda2 none swap sw 0 0 #/dev/sda3 / ext3 errors=remount-ro 0 1 #/dev/sda5 /home ext3 defaults 0 2 UUID=e1fa161b-b014-4a6b-831a-9d8f9e04be07 / ext3 errors=remount-ro 0 1 UUID=88aa922a-4304-406e-8abd-edc2e9064d79 /boot ext2 defaults 0 2 UUID=6ed19886-1cba-47b2-9ce0-7c2ea8f9c3c9 /home ext3 defaults 0 2 UUID=22b881d5-6f5c-484d-94e8-e231896fa91b none swap sw 0 0
by the way, the Ubuntu installer shows the RAID array and not the partitions. See also https://bugs.launchpad.net/ubuntu/+bug/973147