Hitchhiker's Guide to Openbsd

Keeping Things in Sync
It is important to understand that OpenBSD is an Operating System, intended to be taken as a whole, not 
a kernel with a bunch of utilities stuck on. You must make sure your kernel, "userland" (the supporting 
utilities and files) and 
ports
 tree are all in sync, or unpleasant things will happen. Said another way 
(because people just keep making the error), you can not run brand new 
ports
on a month old system, 
or rebuild a kernel from -current source and expect it to work with a -release userland. Yes, this does 
mean you need to upgrade your system if you want to run a new program which was added to the ports 
tree today. Sorry, but again, OpenBSD has limited resources available. 
One should also understand that the upgrade process is supported in only one direction: from older to 
newer, and from -stable to -current. You can not run 4.9-current (or a snapshot), then decide you are 
http://www.openbsd.org/faq/faq5.html (4 of 26)9/4/2011 10:02:02 AM

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5 - Building the System from Source
living too dangerously, and step back to 4.9-stable. You are on your own if you choose any path other 
than the supported option of reloading your system from scratch, do not expect assistance from the 
OpenBSD development team. 
Yes, this does mean you should think long and hard before committing yourself to using -current. 
5.2 - Why do I need to compile the system from source?
Actually, you very possibly do not. 
Some reasons why NOT to build from source: 
●
Compiling your own system as a way of upgrading it is not supported. 
●
You will NOT get better system performance by compiling your own system. 
●
Changing compiler options is more likely to break your system than to improve it. 
Some reasons why you might actually wish or need to build from source: 
●
Test or develop new features. 
●
Compiling the system puts a lot of stress on the computer, it can be a way to make sure the 
system you just put together or acquired is actually in pretty good operational condition. 
●
You wish to follow the 
stable branch.
 
●
You wish to make a highly customized version of OpenBSD for some special application. 
The OpenBSD team puts out new snapshots based on -current code on a very regular basis for all 
platforms. It is likely this will be all you need for running -current. 
The most common reason to build from source is to follow the -stable branch, where building from 
source is the only supported option. 
If you are compiling -current from source, it is HIGHLY recommended that you only do so from a 
machine which you have full console access to. There will be times in the development process where 
the mismatch between your new kernel and your old userland may render the system inaccessible via 
network. This is not an issue when properly building -stable.