Indeed the fix from #4 seems to solve the problem for me. I can confirm that the update from #9 is likely right, this is certainly a race condition, sometimes it will boot without problem and other times it gets stuck.
If I run `ls /dev/mapper` from busybox before executing the `udevadm` command, it doesn't show the LVM volumes. Once I run that command, the devices then appear. My drive configuration is as follows: RAID 1 on 2 drives LVM on Software RAID Root partition on LVM, not separate boot partition No encryption This was an out of the box install of 14.04.3 LTS, and should almost certainly be treated as a serious bug -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1335642 Title: mdadm runs into infinite loop and prevents initrd/initramfs phase to finish on boot To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/1335642/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs