63 lines
1.9 KiB
Markdown
63 lines
1.9 KiB
Markdown
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---
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layout: post
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title: Problems after disconnecting LUKS device
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date: 14.01.2013 23:28
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---
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Yesterday I got my 2TB backup disk. I formatted it and then used [LUKS][] to encrypt it and [LVM][] for the Volume Management.
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After I copied some files to the new disk, I unmounted the disk, unplugged it and ...
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### ... Oh, shit.
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I forgot to `cryptsetup luksClose` it.
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That's not a good thing to do. __Always remember to luksClose! It's so much easier__
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So after reconnecting the device, you can't really decrypt and mount it, because it did not get unmapped (`/dev/mapper/name` still exists and so do `/dev/name/*`)
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### No problem, we fix that!
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_(in the following my mapping name is `extern`, change accordingly)_
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First see current status, especially `Open count`
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dmsetup info
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Now remove each mapped device (`-backup` and `-media` for me, I have 2 partiions on the disk):
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dmsetup remove extern-backup
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dmsetup remove extern-media
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Once again check `Open count`, it should be `0` now. If so, go on and remove the mapping:
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dmsetup remove extern
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Now you got rid of all old mappings. Let's try to mount the disk again. Plug it in, then do:
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cryptsetup luksOpen /dev/sdb2 extern
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Type your password.
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If the Volume Groups are missing, use:
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vgscan
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vgchange -ay extern
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Now you can mount your partitions:
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mount /dev/extern/backup /mnt/backup
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Once you're done, deactivate the volume groups and close the crypt device:
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vgchange -an extern
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cryptsetup luksClose extern
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Now remember to always use these two commands after unmounting the device and use the following to open it:
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vgchange -ay extern
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cryptsetup luksOpen /dev/sdb2 extern
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I wrote a little helper script which does exactly these steps as needed. I'll include it in my next post, when I talk about how I use the setup for backups.
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[luks]: https://wiki.archlinux.org/index.php/LUKS
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[lvm]: https://wiki.archlinux.org/index.php/LVM
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