Install CVSup:
pkg_add cvsup-16.1g-no_x11.tgz
The «no_x11″ means that the cvsup program will be text-only. That’s fine.

Create a directory where CVSup’s configuration files and its bookkeeping data directory will be placed:
mkdir -p /usr/local/etc/cvsup

Create /usr/local/etc/cvsup/stable-supfile. This file will be used to tell CVSup to download all OpenBSD source code for the stable release branch you’re interested in, except for the x11, xf4 (both XFree86 related), www files and ports. In other words: everything that is needed in order to rebuild OpenBSD from source (located in /usr/src. We’re not interested in XFree86 for a server system, so we will skip it.

Working example stable-supfile:

*default host=cvsup.ca.openbsd.org
*default base=/usr/local/etc/cvsup
*default prefix=/usr
*default release=cvs tag=OPENBSD_3_4
*default delete use-rel-suffix

*default compress

#OpenBSD-all
OpenBSD-src
#OpenBSD-www
#OpenBSD-ports
#OpenBSD-x11
#OpenBSD-xf4

Create /usr/local/etc/cvsup/ports-supfile. This file will be used to tell CVSup to download the complete OpenBSD ports collection for the stable release branch you’re interested in, except for the x11, xf4 (both XFree86 related), www files and OpenBSD source code. In other words: everything that is needed in order to use the ports system (located in /usr/ports).
Working example ports-supfile:

*default host=cvsup.ca.openbsd.org
*default base=/usr/local/etc/cvsup
*default prefix=/usr
*default release=cvs tag=OPENBSD_3_4
*default delete use-rel-suffix

*default compress

#OpenBSD-all
#OpenBSD-src
#OpenBSD-www
OpenBSD-ports
#OpenBSD-x11
#OpenBSD-xf4

You probably want to change the «default host» in stable-supfile and ports-supfile to some CVSup server nearest to you. Check out this list of CVSup servers to search for one.

For checking out releases newer than OpenBSD 3.4 you must edit the «tag» in stable-supfile to reflect the version you’re interested in. For updates to the ports collection for OpenBSD 3.4 you must do the same. In order to allways download the latest ports, you must set the «tag» to a single dot (.).