GEOM_PART: a quick update on logical partitions

[Dimitry Andric]

On 2009-02-02 20:16, Marcel Moolenaar wrote:
> In case people are wondering: I'm working on proper support for
> logical partitions. This should also allow us to create and
> modify them. Of course when you add or remove a partition, the
> index changes and consequently the device name. I still need
> to find a good solution for that. Currently I'm thinking that
> we should create the device special file that contains the
> sector offset (which is the one constant) and create compatibility
> symlinks. For example:
> 
> 	/dev/da0s2.00000000
> 	/dev/da0s2.0834F7A0
> 	/dev/da0s5 -> /dev/da0s2.00000000
> 	/dev/da0s6 -> /dev/da0s2.0834F7A0
> 
> The idea is that the logical name (i.e. the symlink) change when
> you add or remove a partition, but that all references (i.e. mount
> information) are against the fixed name.

This sector-based ID is a creative approach. :)  In Linux, they just
assign a GUID to each unique partition (or actually, filesystem), and
you can use that to mount it.  It doesn't matter anymore whether you
shift partitions around then...

OTOH, this gives ugly fstabs like:

UUID=cf3de368-9729-4399-b612-2b62f4e98930  /  ext3  relatime,errors=remount-ro  0  1

Also, you need a place to put the GUID, and there may not be room for
this in the filesystem and/or partition.