Comment 2 for bug 183930

After some more attempts, I finally figured out how to get the md3 raid set up the same way as partman does with md[0-2] on the Alternate installer CD. There have been some constant issues that I forgot to mention that may be a factor. Whenever I attempted to repartition sda and set the partition type to FD, as soon as I exited cfdisk the dmraid system would mount md3 forcing me to mdadm -S /dev/md3 so I could repartition sdb. In addition, /dev/sda1 wouldn't show up while /dev/sdb1 did but fdisk -l would show it existed on sda. mdadm didn't see it so I'm not sure if fdisk was getting it out of /proc/partinfo or just assuming it existed. Without it I couldn't create md3 on sd[ab]1, only sd[ab]. Thinking that was part of the problem I tried various ways of getting sda1 to show up including partprobe, various dd zeroings, and repartitioning. I noticed while doing this that cfdisk doesn't set the serial number in the superblock so I used mklabel in parted to set it on both drives first. Finally I repartitioned sdb as ntfs, zeroed the fist 0.5MiB or so of sda, removed the md3 entry from mdadm.conf, and rebooted. I then repartitioned sda as type FD and then sda1 showed up. I then created md3 on sda1 without a second device and rebooted again to make sure it was persistent. I then repartitioned sdb and added sdb1 as a hot-spare and let it resync. After some more reboots and tests, I ran pvcreate on md3 and checked the superblocks - they remained intact this time. I rebooted and double-checked everything then added md3 to vg0 and rebooted. It failed and I ended up in initramfs busybox. I removed it from vg0 and was able to boot again. So there definitely is a problem with booting from a vg with multiple pv devices, at least if they are md. My workaround was to create a new volume group, vg1, that only had md3 in it. I lose some lvm flexibility this way but at least it boots usually. By "usually" I mean that there is an additional error that now pops up every few boots:

device-mapper: table: 254:0: linear: dm-linear: Device lookup failed
device-mapper: ioctl: error adding target to table
Command failed: Not a block device
cryptsetup: cryptsetup failed, bad password or options?

I never get a LUKS passphrase prompt. I can't unlock the volume from initramfs either. All I can do is reboot and try again.

I also noticed a suspicious error on the boot attempt immediately after removing md3 from vg0:
Starting kernel event manager... [ OK ]
 * Loading hardware drivers...
error receiving uevent message: No buffer space available

I found some references to an old kernel bug but this message only showed up once so it may be unrelated.