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Thread: Help: externally access HD with encrypted LVM

  1. #1
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    Question Help: externally access HD with encrypted LVM

    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!

  2. #2
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    Default Re: Help: externally access HD with encrypted LVM

    What I normally do, in that case, is:
    Code:
    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".
    openSUSE Leap 15.4; KDE Plasma 5.24.4;
    testing Tumbleweed.

  3. #3
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    Smile Re: Help: externally access HD with encrypted LVM

    Quote Originally Posted by nrickert View Post
    What I normally do, in that case, is:
    Code:
    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:

    Code:
    #> 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:

    Code:
    #> 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!

  4. #4
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    Default Re: Help: externally access HD with encrypted LVM

    Quote Originally Posted by johannesrs View Post
    However, I don't know how to proceed:
    Try (as root)
    Code:
    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.
    openSUSE Leap 15.4; KDE Plasma 5.24.4;
    testing Tumbleweed.

  5. #5
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    Unhappy Re: Help: externally access HD with encrypted LVM

    Quote Originally Posted by nrickert View Post
    Try (as root)
    Code:
    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?

  6. #6
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    Default Re: Help: externally access HD with encrypted LVM

    Quote Originally Posted by johannesrs View Post
    Seems that I'm in trouble now... Right?
    It looks that way. I have not come across that situation.
    openSUSE Leap 15.4; KDE Plasma 5.24.4;
    testing Tumbleweed.

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