buildkernel before buildworld

[Giorgos Keramidas]

On 2004-11-14 03:41, Gert Cuykens <gert.cuykens at gmail.com> wrote:
> What happens if you first buildkernel before the buildworld ?

If you have previously finished a buildworld and haven't updated your
source tree in the meantime, nothing too bad.  With a /usr/obj tree
around from the previous buildworld stage, you can add options to your
kernel configuration and run buildkernel, or even:

	# cd /usr/src/sys/i386/conf
	# config -g -d /usr/obj/usr/src/sys/CUSTOM CUSTOM
	# cd /usr/obj/usr/src/sys/CUSTOM
	# make depend && make all && make install

If you have just added a single option to the kernel configuration or
have made minor modifications to the kernel source, this will cut down
on the build time.  A lot.  I have used this method while testing kernel
modifications and managed to build, boot, and test more than 10 slightly
different kernels in less than 3 hours.

After an update of the entire source tree though, building a kernel only
may end up with a kernel that is not in sync with the userland.  Then, a
lot of things may break in unexpected ways.  See, for example:

http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/faq/book.html#NLIST-FAILED

If you are not sure things will work without a buildworld, it's wiser to
follow the upgrade procedure recommended in /usr/src/UPDATING.

- Giorgos