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.