Unable to mount root LVM partition

[Freddie Witherden]

Binary package hint: initramfs-tools

Installed Ubuntu using the alternate install CD. Tried both 10.04 and 10.10 alpha (same results for both). Used guided partition w/LVM. (Hence /boot is a normal partition, ext2, / is ext4 on LVM.)

Upon rebooting the system I was dropped to an initramfs prompt on account of the root partition, /dev/mapper/bromine-root not existing. However, use of the lvm utility shows no abnormalities (lvdisplay, pvdisplay, lvscan and pvscan all print out what I would expect them to).

ls of /dev/mapper shows just a control node. System is unable to boot.

System in question had previously been running 9.04 with a very similar partitioning scheme. Worked perfectly.

[Freddie Witherden (freddie-witherden)]

Poking around a bit I have found that, for some reason, the root volume is not available. Hence, running lvm and using lvchange -a y /dev/mapper/bromine-root at the prompt makes the device node appear (and hence I can mount it).

While this does not help me particularly it may help with tracking down the source of the problem.

[Steffen Neumann (sneumann)]

Hi,

I can confirm this problem. I had a working natty with / living on an LVM partition,
with 9 logical volumes in total. Today, I did a do-release-update to test the almost final oneiric.

I am dropped into a busybox shell on earch boot, because all my LVs are "not available".
Then I can lvm lvchange -ay <my logical volume>, exit the busybox shell and continue to boot normally.

I tried to update-initramfs, and update-grub, but still I get this behavior each time.
lvm2 is 2.02.66-4ubuntu3, initramfs-tools are 0.99ubuntu7

This could be a serious problem, unless it is just our two systems.
Anything I can check ?

Steffen

[Steffen Neumann (sneumann)]

I was reading similar bug reports, and it seems to be that the LVM partitions don't trigger a vgscan,
so it might be rather a runtime than an initrd creation problem.

[Steffen Neumann (sneumann)]

The problem persists, I updated oneiric on the laptop to todays -update and -proposed,
without a change. I was also reading #833891, but that doesn't apply because we both don't
have a timeout problem, we're dropped to busybox immediately.
It's probably also not #802626, because our VG does include the root LV.

Yours,
Steffen

[Steffen Neumann (sneumann)]

I can confirm that the problem persists after upgrading to precise pangolin post-alpha today.

[James Keber (james-keber)]

Steffen, have you tried the "--noudevsync" fix from bug #802626?

[Steffen Neumann (sneumann)]

Thanks James,

I followed the comments in that bug, changed the 85-lvm2.rules,
and verified that the change was present in /lib/udev/rules.d
inside the initrd.

I also tried rootdelay=45 and scsi_mod.scan=sync I found
in other reports, also no change. I have attached an initram debug trace.

Thanks,
Yours,
Steffen

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Jan M. Harasym (jharasym)]

I believe I'm experiencing the same (or very similar) bug on 10.04 LTS.

Boot is halted and I'm dropped into a busybox shell, (with the error, file not found /dev/mapper/<server>-root), I can confirm with busybox that the block device is there though, I can also mount it (but this breaks init)

simply pressing ^D brings me to a "Trying to Mount "/" press M for manual recovery or S to skip this"

pressing "M" brings me to my root filesystem, where I can remount,rw and navigate all the files I'd expect to be there, I can even start networking and ssh. (which is the state the machine is in now) however, I've not had a successful runlevel 5 since this problem started.

the volume behaves exactly as expected in regards to pv/vg/lv-display from the maintenance shell.

Attempts at recovery;
* rootdelay=60 [kernel boot parameter]
* update initramfs
* reinstalling grub2
* export/import of LVM volume
* restore of LVM config
* fsck the partition (clean)

I'm currently backing all the files up, so I can reinstall, but will keep the machine around if anybody wants me to try anything.

[Phillip Susi (psusi)]

Is anyone able to reproduce this on 12.04 or later? It seems to work fine for me.

[Launchpad Janitor (janitor)]

[Expired for lvm2 (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for udev (Ubuntu) because there has been no activity for 60 days.]