GEOM label clarification

Manolis Kiagias sonicy at
Fri Oct 16 18:21:31 UTC 2009

PJ wrote:
> If I understand correctly from the manual, giving the labels their slice
> name (/dev/label/rootfs rather than /dev/ad4s1a) will assure that
> regardless of the disk, the boot will be from the disk being booted and
> not from another disk as happened to me recently - the fstab on disk ad4
> was referncing ad12 so the boot was from ad12 rather than ad4.
> The handbook says:
> "By permanently labeling the partitions on the boot disk, the system
> should be able to continue to boot normally, even if the disk is moved
> to another controller or transferred to a different system. For this
> example, it is assumed that a single ATA disk is used, which is
> currently recognized by the system as ad0."
> If the disk is moved to another system, it may no longer be ad0... So
> will it still boot correctly?

In short, yes. I do this routinely all the time.
Assuming of course that the device is connected to a controller that
FreeBSD recognizes.
This should be a non-issue for standard ATA/SATA disks.

> Or should the ufsid labels be used?

The ufsid is also an option if you do not wish to create the labels
The advantage of user-created labels is that they are not 'cryptic' like
the ufsid ones
and you may actually remember them :)

> Will both of these contortions work?

Yes, both will do.

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