Help: externally access HD with encrypted LVM

[johannesrs]

Hi folks. Needing some assistance here.

I have an old HD with opensuse system on it. The main partition is an encrypted LVM.

For several reasons, I can't simply boot a computer with that disk at the moment (and it will be that for a long time).

Since I have a docking station available, I though about simply connecting it and accessing. However, I can't find a way to mount it: clicking on it in the notification either not prompts me for the password and/or worries about permission (tried as root with similar results), and on the command line nothing like vgscan and others find anything.

Can someone please help me on this?

Thanks a lot in advance!

[nrickert]

What I normally do, in that case, is:

cryptsetup luksOpen /dev/sdb5 cr_lvm

Replace "/dev/sdb5" with the appropriate device on your system.

That should make the LVM volumes available under "/dev/mapper", and you can mount from there. These days, I don't need "vgscan", as that seems to be done automatically. But that might depend on what is installed on your system. Some distros do not automatically install "cryptsetup".

[johannesrs]

What I normally do, in that case, is:

cryptsetup luksOpen /dev/sdb5 cr_lvm

Replace "/dev/sdb5" with the appropriate device on your system.

That should make the LVM volumes available under "/dev/mapper", and you can mount from there. These days, I don't need "vgscan", as that seems to be done automatically. But that might depend on what is installed on your system. Some distros do not automatically install "cryptsetup".

Thanks @nrickert, it helped already:

#> ll /dev/mapper 
total 0 
crw------- 1 root root 10, 236 fev  7 11:12 control
lrwxrwxrwx 1 root root       7 fev  7 11:12 cr-auto-2 -> ../dm-2
lrwxrwxrwx 1 root root       7 fev  7 15:30 cr_lvm -> ../dm-7
lrwxrwxrwx 1 root root       7 fev  7 11:12 cr_root -> ../dm-0
lrwxrwxrwx 1 root root       7 fev  7 11:12 cr_swap -> ../dm-1
lrwxrwxrwx 1 root root       7 fev  7 14:32 luks-7583dc6f-415d-4446-8279-16c55b18a0a2 -> ../dm-3
lrwxrwxrwx 1 root root       7 fev  7 14:32 system-home -> ../dm-4
lrwxrwxrwx 1 root root       7 fev  7 14:32 system-main -> ../dm-5
lrwxrwxrwx 1 root root       7 fev  7 14:32 system-tmp -> ../dm-6

However, I don't know how to proceed:

#> sudo vgscan 
  WARNING: PV /dev/mapper/cr_lvm in VG system is using an old PV header, modify the VG to update. 
  WARNING: Device mismatch detected for system/home which is accessing /dev/mapper/luks-7583dc6f-415d-4446-8279-16c55b18a0
a2 instead of /dev/mapper/cr_lvm. 
  WARNING: Device mismatch detected for system/main which is accessing /dev/mapper/luks-7583dc6f-415d-4446-8279-16c55b18a0
a2 instead of /dev/mapper/cr_lvm. 
  WARNING: Device mismatch detected for system/tmp which is accessing /dev/mapper/luks-7583dc6f-415d-4446-8279-16c55b18a0a
2 instead of /dev/mapper/cr_lvm. 
  Found volume group "system" using metadata type lvm2

#> sudo lvs 
  WARNING: PV /dev/mapper/cr_lvm in VG system is using an old PV header, modify the VG to update. 
  WARNING: Device mismatch detected for system/home which is accessing /dev/mapper/luks-7583dc6f-415d-4446-8279-16c55b18a0
a2 instead of /dev/mapper/cr_lvm. 
  WARNING: Device mismatch detected for system/main which is accessing /dev/mapper/luks-7583dc6f-415d-4446-8279-16c55b18a0
a2 instead of /dev/mapper/cr_lvm. 
  WARNING: Device mismatch detected for system/tmp which is accessing /dev/mapper/luks-7583dc6f-415d-4446-8279-16c55b18a0a
2 instead of /dev/mapper/cr_lvm. 
  LV   VG     Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert 
  home system -wi-a----- 296,44g                                                     
  main system -wi-a-----  50,00g                                                     
  tmp  system -wi-a-----   2,00g

I want to mount that lvm home volume in a different directory to find some old files I'm needing. How can I proceed? It is just mount now (and if yes, what path should I mount?), or should I perform some other procedure before?

Thanks a lot!

[nrickert]

However, I don't know how to proceed:

Try (as root)

mount /dev/mapper/system-home

and then look under "/mnt" to find the files you are seeing. You probably don't need to be root, once it is mounted.

For now, I would ignore that message about old PV header.

I'm not sure of those "Device mismatch" messages. Perhaps you currently have another LVM with a name conflict between the two.

[johannesrs]

Try (as root)

mount /dev/mapper/system-home

and then look under "/mnt" to find the files you are seeing. You probably don't need to be root, once it is mounted.

For now, I would ignore that message about old PV header.

I'm not sure of those "Device mismatch" messages. Perhaps you currently have another LVM with a name conflict between the two.

Hi @nrickert.

Now I had no advances.

If I don't "point" the mount command to some destination directory, it complains that it is not in the /etc/fstab. Understandable.

However, if I go further and point the mount command somewhere, say "sudo mount /dev/mapper/system-home /home/user/tmp" (where that is an actually directory that the user user has created), it complains that he can't read the superblock in /dev/mapper/system-home...

Seems that I'm in trouble now... Right?

[nrickert]

Seems that I'm in trouble now... Right?

It looks that way. I have not come across that situation.