[dm-crypt] help mounting partitions in an encrypted disk after first reboot

Arno Wagner arno at wagner.name
Sun Jun 18 20:03:24 CEST 2017

On Sun, Jun 18, 2017 at 19:21:57 CEST, Julio Gago wrote:
>  ---- On Sun, 18 Jun 2017 17:40:54 +0200 Arno Wagner <arno at wagner.name> wrote ---- 
>  > Hi Julio, 
>  >  
>  > the partitions do not show up on reboot as the kernel cannot 
>  > see them. The partition table it would need to scan is 
>  > in the encrypted LUKS container and as that is still 
>  > closed on boot, hence the kernel has no chance to look at it. 
>  >  
>  > A fix might be to just call "partprobe" after opening the 
>  > LUKS container. That scans all reachable devices for 
>  > partition tables. It also works directly after repartitioning, 
>  > i.e. without a reboot. 
>  >  
>  > partptobe is part of the parted package (at least on Debian). 
> Thanks Arno!!!!
> That fixed it!!!!
> I was so close to finding this :).  I can see in my history that I tried
> with "partx" (it does the same, in theory, or something similar in the
> realm of my understanding) and that I did "man partprobe", probably saw it
> in the "see also".
> I am wondering if we should add a section about this in the FAQ.  Or maybe
> this is not frequent enough?
> I volunteer myself to do the update to the FAQ if you guys want.
> Julio

You are welcome.

I think I will do an  FAQ item on "Partitioning a LUKS container", 
that would also describe this effect and the need for partprobe or 
something like it.

And yes, this is rare. I believe this is the first time somebody
had this problem. Most people will use unpartitioned LUKS
containers or use LVM.


Arno Wagner,     Dr. sc. techn., Dipl. Inform.,    Email: arno at wagner.name
GnuPG: ID: CB5D9718  FP: 12D6 C03B 1B30 33BB 13CF  B774 E35C 5FA1 CB5D 9718
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