Lvm – Grub2 reports physical volume pv0 not found on server non bootable anymore

I first installed my ubuntu server (11.10 amd64) using lvm but not fully mastering the concept of it. I think that's partly what made the mess of partitions on my two disks (seems to me). I installed everything using grub2 from the start to boot my Ubuntu, which I updated later to Ubuntu Server 12.04, no problem.

Here is the situation:

• As of today, I can't boot at all, stuck with no evolution at what seems to be just before the grub options (Edit: precision from Pavel A.);

• I can boot using the server install liveCD with option Rescue a broken system;

• I setup network access, but don't seem to have a /run folders (don't know if it's related but seemed abnormal in some forums);

• The devices map I built is as follows:

  1. VGa contains sda1 [Linux partition], sda2, sda3 [/] and sda5(the latter seems the same as sda3, same descriptors)
  2. VGb contains sdc1, sdc2 [/boot] and sdc3 [/home]

  (the two do not have the same PE or LE, but I'd like ultimately to have everything in the same VG)

• Last thing I did to the boot environment was to (cleanly) remove older kernels from the boot partition (236MB large, was 99% full);

• I ran grub-install (after having mounted boot) but got various errors:

  • can't install on /dev/sdabecause core.imgwon't fit (first partion starts on 32)
  • output of grub-install on /dev/sdc exhibits error physical volume pv0 not found
  • I even tried to grub-install directly to /dev/sda5, apparently with no error, but with no success at boot either

I looked here [serverfault]: Grub2 reports physical volume pv0 not found when probing/installing
I looked here [Ubuntu forums]: SOLVED] Install kernel with liveCD & fix grub2
I looked here [Ubuntu help] : Fixing a Broken System
I looked here [ubuntu forums]: [SOLVED] 10.10 Maverick – Grub won't recognize my Windows partition

None of what I did changed anything to the stuck-boot-situation (I can't define it any better: it just hangs, for minutes and minutes and minutes).
I hope I've not left out any important detail.

I have no idea what to do anymore, especially if installing grub doesn't work. I've not lost any data, but as it was a production(-ish) server (i.e. entirely personal), I now strongly feel the need for mirrors (I already set backups but… on the server :p).

Anyway, if any of you geniuses had any idea or lead, that would be a great help.

Thank you

Valentin

Edit: tail /var/log/syslog yields no output (blank), no new syslog is created that I can see

Edit2: I used the Boot Repair CD (Ubuntu Secure Remix version) and generated the following report on the state of my boot: http://paste.ubuntu.com/1620777