Hitchhiker's Guide to Openbsd

4.15 - How can I install a number of similar systems?
Here are some tools you can use when you have to deploy a number of similar OpenBSD systems. 
siteXX.tgz
 and 
install/upgrade.site
 files
See the 
above
article. 
Restore from dump(8)
On most platforms, the boot media includes the 
restore(8)
 program, which can be used to restore a backup made by 
dump
(8)
. Thus, you could boot from a 
floppy
, 
CD
, or 
bsd.rd
 file, then 
fdisk
, 
disklabel
, and 
restore
the desired configuration 
from tape or other media, and install the 
boot blocks
. More details 
here
. 
Disk imaging
Unfortunately, there are no known disk imaging packages which are FFS-aware and can make an image containing only 
the active file space. Most of the major disk imaging solutions will treat an OpenBSD partition as a "generic" partition, 
and can make an image of the whole disk. This often accomplishes your goal, but usually with huge amounts of wasted 
space -- an empty, 10G 
/home
partition will require 10G of space in the image, even if there isn't a single file in it. 
While you can typically install a drive image to a larger drive, you would not be able to directly use the extra space, and 
you would not be able to install an image to a smaller drive. 
If this is an acceptable situation, you may find the 
dd
 command will do what you need, allowing you to copy one disk to 
another, sector-for-sector. This would provide the same functionality as commercial programs without the cost. 
4.16 - How can I get a dmesg(8) to report an install problem?
When 
reporting a problem
, it is critical to include the complete system 
dmesg(8)
. However, often when you need to do 
this, it is because the system is working improperly or won't install so you may not have disk, network, or other resources 
you need to get the dmesg to the appropriate 
mail list
. There are other ways, however: 
●
Floppy disk: The boot disks and CD-ROM have enough tools to let you record your dmesg to an MSDOS floppy 
disk for reading on another machine. Place an MSDOS formatted floppy in your disk drive and execute the 
following commands: 
http://www.openbsd.org/faq/faq4.html (42 of 43)9/4/2011 10:01:58 AM

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4 - OpenBSD 4.9 Installation Guide
mount -t msdos /dev/fd0a /mnt
dmesg >/mnt/dmesg.txt
umount /mnt
If you have another OpenBSD system, you can also write it to an OpenBSD compatible floppy -- often, the boot 
floppy has enough room on it to hold the dmesg. In that case, leave off the "
-t msdos
" above. 
●
Serial Console: Using a serial console and capturing the output on another computer is often the best way to 
capture diagnostic information - particularly if the computer panics immediately after boot. As well as a second 
computer, you will need a suitable serial cable (often a null-modem cable), and a terminal emulator program that 
can capture screen output to file. 
General information on setting up a serial console is provided 
elsewhere in the FAQ
; in order to capture a log of 
the install, the following commands are usually sufficient.