what is the process for migrating a pre-built kernel to a new machine?

Jason C. Wells jcw at highperformance.net
Sun Mar 26 05:43:21 UTC 2006

Jonathan Horne wrote:
> What if I want to use a kernel I compiled on one system, on another system?
> What is the process to successfully migrate a kernel from one system to
> another (or back to the same after a disaster recovery)?

Just FTP, NFS, or otherwise copy the kernel to the new system and reboot.

Now for the caveats.  It is inadvisable to copy a kernel from one 
version of FreeBSD to another.  You'll get mysterious library errors 
from libraries like libkvm.  Copying 6.1 kernels to and from 6.1 systems 
is OK.  Copying 6.1 kernels to 5.4 system is bad.  Copying a kernel from 
last month's build of stable to this months build of stable is probably 
bad also.

I would advise you to install the kernel sources on each machine where 
you want to build a custom kernel.  That or set up one machine to be 
your "build server" in the fashion described in the handbook.

You also have to take care regarding hardware compatibility.  If one 
system is all SCSI and the other is all IDE you are not going to be able 
to move those kernels around and have properly functioning hard drives.

For disaster recovery, keep your kernel config file.  I would argue that 
the config file is more important than the actual kernel binary.

Jason C. Wells

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