Long time lurker, first time poster, having spent 2 days searching now to no avail!
I am new to Linux/Ubuntu, hence putting this in the Beginners section. But I learn quick. Since first 'testing out' Ubuntu 3 weeks ago, Windows has disappeared entirely from my digital life (and hard drive), and I'm learning more about computers than ever before. But I think I may have gone in over my head a bit here. Please forgive the essay below - the problem is a little unusual
I'm running 12.04 on a laptop (with UEFI BIOS), with full disk encryption set up up using the Alternate CD. I recently made a backup image of the entire hard drive using dd, to an external USB hdd. Having recently made some changes on the laptop, I tried to plug in the external USB clone to copy the files to it. Despite getting the password prompt and having it appear in the Disk Utility as a logical volume group, it would not actually mount the external drive, saying it was 'not a mountable file system'. Tried it on my desktop, and it mounted up just fine (once I installed lvm2).
Using pvdisplay, I noticed that both the external drive and internal laptop drive had the same UUID (duh, it's a clone!). So, on the desktop, I used pvchange -u to change the external drive's uuid. Plugged it into the laptop, alas, still no joy. Gave up, turned off the laptop (drive still plugged in), went and had dinner. Came back, unplugged external drive from now-off laptop, tried to boot. Problems!
It boots to the password prompt screen like normal. Enter the password, and after a long wait, it drops to an initramfs prompt, with the error:
"ALERT! /dev/mapper/ubuntu-root does not exist."
If I reboot, and plug back in the external drive, it boots up, seemingly running root off the USB drive. I have tried the solution here, entering /dev/sda3 (and yet more variants) instead. No bingo, still get exactly the same messages. The fact I'm using LUKS with a LVM seems to complicate things. I think I've muddled a config file somewhere, probably by plugging in two drives with the same UUID (stupid!) and now it thinks /root is on the external drive. I'm stumped as to how to get it back.
Any help would be really appreciated. Thanks in advance (especially if you read all that).
Removed the internal laptop drive, plugged it into my desktop and it wouldn't read it.
Ran lvscan and pvscan, and it doesn't pick it up as being part of a logical volume group.
Did the same thing to the backup clone: detects it just fine. Belongs to the 'ubuntu' volume group, mounts everything OK.
Any ideas? Anyone??
C'mon, no-one? I'm really up the creek without a paddle here, and I need to get this thing back on-line for work in the new year. Even if I can just find a way to read the encrypted volume off another computer to I can salvage my un-backed up data.
The crux of the issue seems to be that the internal laptop drive has a logical volume, but doesn't seem to have a logical volume group. Is there any way to re-create the volume group without nuking the logical volume?
And I'm serious about the beer.