ubuntu - Grub2 reports physical volume pv0 not found when probing/installing

I upgraded a Ubuntu Maverick to Precise server but I get the following error while updating grub:

error: physical volume pv0 not found.

Now, for my system I have /dev/sda through /dev/sde

• /dev/sda1 is a Linux partition for /boot


• and /dev/sda5 is an LVM partition


• /dev/sdb through /dev/sde are PVs for the LVM

By looking at my vg config, pv0 is /dev/sda5

I only have one Volume Group called "ns2" where the root (/) and some other logical volumes for the system.

I tried looking on the Web for help but they said I should upgrade to Grub2 as it is better to LVM support. I did that and I get the same error.
I haven't rebooted the server but I have the feeling it is not going to boot.
Still, I want to fix that error.

My boot partition is not in an LVM volume so even grub1 or grub2 should look at it without problems.

Any ideas?
I just tried reinstalling grub but I get the same error, still it seems to go "fine".

What can I check before rebooting?
This server is in another location and I have no remote access to the console, so I want to go there ready if something needs to be done.

Edit: Added more information http://pastebin.com/Smr1pB8W

Edit: Added pvs information http://pastebin.com/yubMd232

Answer

It sounds like you didn't reboot between upgrading LVM2/GRUB and the kernel.

You will want to "pin" an old grub version long enough to reboot your system into a current kernel version. At that point you should be good to unpin, upgrade grub and everything should be kosher.

Add this to /etc/apt/preferences:

---

# Force grub to 1.98+20100804-5ubuntu3

Package: grub-pc

Pin: release n=maverick

Pin-Priority: 1000

---

Now apt-get update && apt-get -s dist-upgrade. Assuming you get a line like "Inst grub-pc [ 1.98+20100804-5ubuntu3] ...." (and the resulting dependency shuffling doesn't break your system... watch for things like libc downgrades) you can "apt-get dist-upgrade" to force grub back to sanity. I would suggest running "update-grub" one more time to make sure you're not walking into an un-bootable situation.

Let me know how it goes :)