Re: mbrlabel question

[mlelstv%serpens.de@localhost (Michael van Elst)]

ea1abz%gmail.com@localhost (Ramiro Aceves) writes:

>     The following options are available:
>     -f         Force an update, even if there has been no change.
>     -q         Performs operations in a quiet fashion.
>     -r         In conjunction with -w, also update the on-disk label.
>     -s sector  Specifies the logical sector number that has to be read from
>                the disk in order to find the MBR.  Useful if the disk has
>                remapping drivers on it and the MBR is located in a non-
>                standard place.  Defaults to 0. 
>     -w         Update the in-core label if it has been changed.  See also -r.

>I do not know the difference between the in-core and on-disk options,
>what I should use and if I can break something with it.


The BSD partition information (aka "disklabel") exists in memory ("in-core")    
and is also written to disk ("on-disk").

If you change only in-core, the change is temporary and volatile. When
the disk is no longer in use, or after a reboot, the changes are gone.

For permanent changes you need to write the on-disk label.

I.e. use

    mbrlabel wd0

to show how the disklabel would look like, and use

    mbrlabel -rw wd0

to actually change the disklabel permanently.