[dm-crypt] Cryptsetup FAQ montly pointer 8/13

Arno Wagner arno at wagner.name
Sat Aug 3 19:47:53 CEST 2013

On Sat, Aug 03, 2013 at 04:10:29PM +0200, Dragan Milivojević wrote:
> > Another option for reliably identifying the swap partition is to use
> > /dev/disk/by-id/<identifier> to identify the drive by model and serial
> > number.  For example, my own swap partition is
> >
> >     /dev/disk/by-id/scsi-SATA_ST95005620AS_5YX1NEGE-part5
> >
> > That should be safe unless I re-purpose that drive and forget to update
> > /etc/crypttab.
> I would suggest using UUID. It works in all cases (partition, raid,
> lvm member etc).
> My crypttab (encrypted swap/home):
> luks-4dc17e23-e895-4e4b-8061-114fb33c310b
> UUID=4dc17e23-e895-4e4b-8061-114fb33c310b none
> luks-46969c48-ab1f-4bd7-bc2a-ae7c1bc86b26
> UUID=46969c48-ab1f-4bd7-bc2a-ae7c1bc86b26 none
> This was generated by fedora install.

It does not work for encrypted swap. And it cannot work,
as the UUID is stored in the partition itself. Just the same
as an empty partition does not have an UUID...

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
There are two ways of constructing a software design: One way is to make it
so simple that there are obviously no deficiencies, and the other way is to
make it so complicated that there are no obvious deficiencies. The first
method is far more difficult.  --Tony Hoare

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