Re: [dm-crypt] LUKS header always disappears after reboot

[Arno Wagner <arno@wagner.name>]

On Thu, Jan 05, 2012 at 08:11:31PM -0500, Cory Coager wrote:
> On 01/05/2012 03:11 AM, Arno Wagner wrote:
> > Well, that is not a LUKS header, that looks like an EFI MBR
> > or bootsector. There is no trace of the LUKS header.
> >
> > Either something is writing this to your disk
> > or, if this is an USB disk, the USB-to-SATA controller in
> > the disk may be doing this in violation of the spec, probably
> > in a misguided atempt to make this thing usable under Windows.
> >
> > Is this really /dev/sdb1 and not /dev/sdb and is the partition
> > still there?
> >
> > As to your data, unless you have a LUKS header backup, it is 
> > very likely gone. 
> >
> > Here is something you can try: Zero the first GB or so of
> > the drive, sync, reboot and see whether anything is on it.
> > Then do the same, but unplug the drive while the computer
> > is on and hotplug it after booting. And finaly do the same
> > and unplug and replug the drive without booting the computer.
> > That could give indication of whether the drive is doing 
> > something by itself or whether the PC is writing something. 
> >
> > Arno

> OK, I have a good deal of information of what the problem is.  The issue
> seems to happen on two specific computers but not a third.  They aren't
> recognizing the entire hard drive size.  fdisk is showing 3tb for
> /dev/sdb but if I run fdisk on /dev/sdb1 it only shows 2199 GB for size.
> 
> Now, when I connected this drive to the third machine, it works
> perfectly.  My data is still intact, I can see the LUKS header and I can
> mount the file system.

Aha, so this is some broken mapping for large drives.
Then the EFI header could be something left over that
does not matter at all.
 
> Now that I've narrowed down the issue, how can I resolve it?  Why can't
> these two computers see the entire drive size?
>
> Both are custom builds, the drive was connected directly via SATA
> 
> Computer #1
> Abit KN8 Motherboard
> BIOS version 6.00 PG
> AMD Athlon(tm) 64 Processor 3200+
> 
> Computer #2
> Asus A8N32-SLI-Deluxe Motherboard
> BIOS version 1303
> AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
> 
> 
> Do you think I need a BIOS update or am I missing something in the OS?

I suspect that a BIOS update is necessary. For older boards that
coul be problematic. There may also be a hardware limitation in 
there somewhere, I am not sure. 

It may be a good idea to use the drives only via USB on the older
computers.

However, not a cryptsetup problem, so let us take this off the list.

Arno
-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name 
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
----
One of the painful things about our time is that those who feel certainty 
are stupid, and those with any imagination and understanding are filled 
with doubt and indecision. -- Bertrand Russell