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This is kind of a strange situation, but basically, I need to somehow mount some xen guest images (which were made from LVMs) and look into their directory structure. kpartx can do this...

That's easy; except for the fact that my restore area is NOT the same server in which these LVM images were created from, meaning I don't have access to the system which had the physical disks. All I have is a backup of the entire system SEE EDIT (a image which I've extracted into a directory structure). So basically I have another root filesystem under /restore, which I can chroot to.

I'm not sure what I'm trying to do is even possible. Anyone have any idea about this at all?

TL;DR: trying to mount xen images that are logical volumes, except NOT on the server (or disks) the original LVMs configuration was done. I have the /etc/lvm/backup/etc files, but I'm really at a loss here on how I can use this...

Bonus: the disks in which the original LVM configuration were created was in a software RAID.

** It wasn't an "image", but a filesystem backup, so I'm SOL w/o the disks themselves...

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Tell me that the VG at least has a different name... –  Ignacio Vazquez-Abrams May 12 '11 at 20:55
    
Yes, the names are different. –  user81307 May 12 '11 at 21:04
    
What kind of image? Do you still have it, or only the useless extracted directory structure? –  Turbo J May 14 '11 at 3:21

2 Answers 2

If you in fact only have a filesystem dump from the old (and I assume broken?) Xen dom0 root you won't be able to recover your logical volumes. They aren't part of the dom0 filesystem but act as something very much like partitions/block devices, as you probably know.

Note that if you had a way to get your actual logical volumes to the new server (by inserting a member of the RAID 1 array, for example) you should be able to use them by running pvscan, vgscan and lvscan.

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What kind of software raid? md? In this case, if you've taken the image off your mdX device, it would be transparent anyway - nothing to worry about.

If you have the image in a file, you might use "losetup" to set up a loop block device and then use the typical "vgscan" / "vgchange", "pvscan", "lvscan" sequence to bring the volume group, the physical and the logical volumes online.

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I phrased my original post wrong (see edit; long day). I will need to take to take an image of the disks (software raid dev). So you are correct, if I had the image. –  user81307 May 12 '11 at 21:52
    
Hmm, so you have a copy of the root filesystem mounted as /restore, I understand that. But how do you think you will be able to access your logical volumes if they would not have been part of the file-based copy in the first place? They would have appeared as block device nodes in /dev/<vgname>/<lvname> in the original root filesystem, but typically you would have excluded those from a backup copy done with tar or rsync. –  the-wabbit May 13 '11 at 23:54

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