Rebuild instructions for amd64 systems

Matt Szubrycht matts at
Wed Nov 4 04:32:23 UTC 2009

Hi Richard,

Kernel recompilation part of the handbook is fairly straightforward  
and should walk you through step-by-step without any snags:
Just remember to use amd64 instead i386 in the examples @ the link  
above.  You will need full source tree to play with kernel (sysinstall  
to the rescue if you don't).

Disclaimer - the below worked for me multiple times and may or may not  
work for you.  If you decide to follow the steps outlined below and it  
breaks your box, spills your coffee or converts the datacenter into a  
recycling center, you are responsible for it and I cannot be held  
accountable in any way.  In other words - use at your own risk.

The way I do it (6.0-RELEASE) - at this point you must be root:

mkdir kernels
cd /usr/src/sys/amd64/conf

vim NEWKERNEL, search for
and change to NEWKERNEL

then, add the following line below all other 'options' lines:
options     PAE             # large memory (>4G) support

then, find and comment out these two lines to avoid a conflict with PAE:

device adv		# Advansys SCSI adapters
device	adw		# Advansys wide SCSI adapters

I am not sure about the Advansys conflict in versions newer than 6.0.
A total of 4 lines to edit on of my stock 6.0-RELEASE GENERIC kernel.


cd /usr/src
make buildkernel KERNCONF=NEWKERNEL
if compiles, install:
make installkernel KERNCONF=NEWKERNEL

once that's done, reboot and you should see your new kernel

Here's a diff from my 6.0:

[root at banksy /usr/src/sys/i386/conf]# diff BANKSYPAE GENERIC
< ident		BANKSYPAE
 > ident		GENERIC
< options		PAE			# 2006-12-12 Large memory support matts at
< # conflicts with PAE device		adv		# Advansys SCSI adapters
< # conflicts with PAE device		adw		# Advansys wide SCSI adapters
 > device		adv		# Advansys SCSI adapters
 > device		adw		# Advansys wide SCSI adapters

Good luck.

Matthew Szubrycht

On Oct 29, 2009, at 8:52 PM, Richard Gehlbach wrote:

> I am installing FreeBSD 7.2 / amd64 on a new server (HP DL370 G6)  
> with 2 quad Xeon processors and 16GB memory.  I have worked with the  
> i386 versions since version 3.x, but this is the first server large  
> enough to need amd64.
> I have been trying to determine the correct procedures for  
> rebuilding the world and kernel.  I have not been able to find a  
> location that had step by step instructions, similar to the  
> handbook, for properly working with the amd64 version.  Searches  
> have turned up so many fragments of what needs to be done, that I  
> cannot feel confident trying to put the pieces together.
> I need instructions for the command line compile options, conf file  
> additions, and any special instructions.
> If anyone can point me to some applicable links or some specific  
> instructions, it would be appreciated.
> Richard
> -- 
> Richard D. Gehlbach                   Gehlbach Consulting Services
> rdgehlba at                 3321 Pepperhill Ct.
> 859.269.6658  Fax 859.266.7446        Lexington, KY  40502
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