Re: [dm-crypt] Broken header of a luks-partition - more than once

[test532@codingninjas.org]

Or, to prevent any chance of the BIOS swapping the disk order, you could refer 
to your device by id instead. I know my friends motherboard does that, it 
randomly sometimes swaps the disk order for no reason when booting, just some 
bug in the bios.

So, to refer to disks in a way that are guaranteed to always point the the 
exact physical disk you want, regardless of what order they are, check in the 
/dev/disk/by-id directory. In here the kernel creates files that point to your 
disks just like /dev/sda, /dev/sdb, etc, do, except that instead of some 
arbetrary name like /dev/sda, the name is based upon the interface, the make 
of the drive, and its serial number.

Regards,
Sam

> I was too hasty, this should have gone to the list...
> 
> On Mon, Aug 24, 2009 at 08:08:57PM +0200, Arno Wagner wrote:
> > On Mon, Aug 24, 2009 at 05:55:37PM +0200, Milan Broz wrote:
> > > spamzad@googlemail.com wrote:
> > > > Something must have overwritten the header (posted it at the bottom)
> > > > - and I have no clue what.
> > > > That's exactly my question now: might it be a bug in cryptsetup or
> > > > can i rule that out?
> > >
> > > Cryptsetup never write empty first sectors except explicit LUKS format.
> > > (Of course this can very rarely happen if hw/driver problem appears...)
> > >
> > > But see crypttab here - you have tmp device created as regular
> > > encrypted device
> > > with random key - are you sure that kernel _cannot_ swap sda & sdb and
> > > your system just formats temp device here?
> >
> > I had that happen to me. Nasty. The BIOS seemd to modify disk order
> > when booting from a different drive via the bootup boot device
> > selection.
> >
> > One simple way to get around this is to create one-drive RAID1
> > devices and then use them. No moving by the kernel on these.
> >
> > Arno
> >
> > > > # <target name> <source device>         <key file>      <options>
> > > > home            /dev/sdb2               none            luks
> > > > ctmp            /dev/sda2               /dev/urandom
> > > > tmp,cipher=aes-cbc-essiv:sha256
> > > > cswap           /dev/sda5               /dev/urandom
> > > > swap,cipher=aes-cbc-essiv:sha256
> > >
> > > Milan
> > > --
> > > mbroz@redhat.com
> > >
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> > > dm-crypt@saout.de
> > > http://www.saout.de/mailman/listinfo/dm-crypt
>