[CentOS] Retrieving files from dd backup

Fri Nov 27 07:11:33 UTC 2020
Ralf Prengel <ralf.prengel at rprengel.de>

Simple question
did you try a centos live cd with a all tools to open the system?
Perhaps the easiest way when not trained every day restoring files.
Ralf

Von meinem iPad gesendet

> Am 26.11.2020 um 20:11 schrieb H <agents at meddatainc.com>:
> 
> Running CentOS 7 I have a previously combined backup of a disk with three partitions using dd. I now need to restore one single file from this backup and after perusing the internet, specifically https://unix.stackexchange.com/questions/31669/is-it-possible-to-mount-a-gzip-compressed-dd-image-on-the-fly, I have done the following:
> 
> - installed squashfs-tools
> 
> - installed kpartx
> 
> - made a squash image of the dd backup and mounted it
> 
> - used kpartx to create devices for the three partitions under /dev/mapper/loopNpP
> 
> - I can now mount the first partition, which is the EFI partition, and access it
> 
> - the second partition, the boot partition, fails to mount since it has the same UUID as the disk I am using in the computer, and of which it is an earlier dd backup. Since I am not interested in the boot partition - at least not right now - I moved on.
> 
> - I am, however, interested in the third partition which is LUKS encrypted. Running 'cryptsetup luksOpen /dev/sda3 my_encrypted_volume' I can decrypt it with the password
> 
> - trying to mount the decrypted version with 'mount /dev/mapper/my_encrypted_volume /media/my_device' results in a failure message 'mount: unknown filesystem type 'LVM2_member'
> 
> - another website, https://askubuntu.com/questions/766048/mount-unknown-filesystem-type-lvm2-member, suggests I could run vgdisplay to get the UUID and then rename it using vgrename
> 
> But, vgdisplay shows only one vg and I am afraid to rename the VG UUID shown by vgdisplay since it might refer to the VG currently in use...
> 
> Does anyone have any insight or suggestions into the above and how to proceed while being absolutely certain I will not be messing up the running part of the system?
> 
> Thanks!
> 
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