I solved the problem, it has two related bug reports here, but I can't find them anymore.
The problem was that apparently fdisk has a bug, which lets it create partitions which are 1 cylinder larger than the disk. If you install raid on such a system anything could happen. The raid will not start or randomly etc. I solved it by manually creating the 4 primary partitions on the disks with fdisk and than used the standard server install to setup raid+lvm on it. works like a charm. -- ubuntu server 10.04amd64 fails to boot after installation on lvm+raid5 https://bugs.launchpad.net/bugs/625169 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs