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Author Topic: Kernel not recognizing LVM-volumes  (Read 3164 times)

Offline sm8ps

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Kernel not recognizing LVM-volumes
« on: June 24, 2021, 04:36:22 AM »
Hello again!

I have been trying to set-up dCore Focal on a laptop where some protected data is enclosed in a LUKS/LVM-container. After jumping through some hoops, I got LVM to find its volumes via 'lvs'. However, the kernel does not reproduce them under '/dev/mapper' or anywhere else. I have the following extensions loaded:
Code: [Select]
Without the wireless extensions there are quite some packages missing like liblz4, something like gcrypt and possible some more. The RAID extension is necessary to provide the dm_mod kernel module as per the forum thread kernel device-mapper driver(http://forum.tinycorelinux.net/index.php/topic,16127.15.html). I threw in the Truecrypt, Mdadm packages in the hope that they might solve the problem but this was not the case.

dCore still is a fascinating marvel in the Linuxiverse. Cheers!

Offline Rich

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Re: Kernel not recognizing LVM-volumes
« Reply #1 on: June 24, 2021, 07:55:37 AM »
Hi sm8ps
Did you compare the list that Jason W attached here:
to what you have installed?

These in particular stand out:
Code: [Select]

Offline sm8ps

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Re: Kernel not recognizing LVM-volumes
« Reply #2 on: June 24, 2021, 10:12:07 AM »
Thanks for your suggestion, Rich! I did notice there was a list but had not inspected it. Now I simply made an extension of the full list and had it loaded at boot-time. There is no difference in behavior, though. I issued a magic 'udevadm trigger' but that did not change anything either.
For completeness: '/dev/mapper/' exists but only contains
Code: [Select]
crw-------  1 root root 10, 236 Jun 24 16:08 control

Offline sm8ps

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[SOLVED] Kernel not recognizing LVM-volumes
« Reply #3 on: June 25, 2021, 06:45:47 AM »
As usual, the error was on my side.  :) The following steps are necessary to use LVM-volumes on dCore-bionic:
  • sce-load lvm2. On its own, it is not functional as it is missing dependencies like liblz4 etc.
  • sce-load wireless. Provides the missing dependencies.
  • sce-load raid-dm-<KERNEL>-tinycore64. Provides and loads the dm_mod kernel module.
  • vgchange -ay
Steps 1-2 give a functional set of LVM-tools. Step 3 introduces device mapper. However, it does not automatically activate the LVM-volumes as I had expected. This needs to be done manually as in step 4.

This is a bit a work-around rather than a fully automated set-up. Especially step 2 is not very intuitive and could be replaced by a dependency to lvm2. Though, as long as I am the only one using it or, respectively, others using it are happy with this approach, it is quite alright. Together with cryptsetup, things are working as I had hoped.