After the update from wheezy to jessie this system didn't boot anymore; it stuck with the (initramfs) prompt. The situation was very similar to other bugs, whose solution was addressed with bug #678696:

- /dev/disk/by-uuid/ wasn't created
- Error message "Gave up waiting for the root device"
- Error message ALERT! /dev/disk/by-uuid/-xy- does not exist
- (initramfs) prompt

I found out I could arrive at a mountable md0 with a rescue system using modules dm_mod and md_mod (etc.). (Yes; there's an md raid on top of a dm raid. Don't ask me; the system is inherited.) The order was decisive here; if I loaded md raid before dm raid, I arrived at unusable devices md126 and md127, which I couldn't mount and which didn't have a blkid.
So I tried the same inside initrd, where also the devices md126 and md127 showed up, and after rmmodding all dm-raid and md-raid modules, insmodding dm_mirror, doing a dmraid -ay and insmodding raid1, I arrived at usable /dev/disk/by-uuid/- entries and md0-array and could boot the system.

I think this constellation hasn't been adressed by the event based block device handling patch referenced in bug #678696.

Putting PREREQ=dmsetup in /usr/share/initramfs-tools/hooks/mdadm and doing an update-initramfs didn't help.

This is initramfs-tools 0.120 with jessie and wasn't a problem with initramfs-tools 0.109.1 under wheezy as far as I can reconstruct.


Best regards, jo

Control: reassign -1 dmsetup
anymore; it stuck with the (initramfs) prompt. The situation was very
similar to other bugs, whose solution was addressed with bug #678696:
using modules dm_mod and md_mod (etc.). (Yes; there's an md raid on top
of a dm raid. Don't ask me; the system is inherited.) The order was
decisive here; if I loaded md raid before dm raid, I arrived at
unusable devices md126 and md127, which I couldn't mount and which
didn't have a blkid.
[...]

I don't believe this has ever been a supported configuration, and it
may have only worked by chance before.

In any case, setup of RAID devices is handled by scripts that come from
other packages, so I'm reassigning this to dmsetup.

Ben.