Re: request: LOADER_ZFS_SUPPORT

On Tue, 17 Nov 2009, Miroslav Lachman wrote:

>> Possibly freebsd-update should be maintained as part of the release process 
>> and not by someone at arm's length to the re team. In recent times it has 
>> broken rebooting after an update twice: once because of the above issue, 
>> and earlier when updating from 7.2 to 8.0-beta it was impossible to install 
>> a new kernel, reboot and then install world. This wasn't a freebsd-update 
>> specific issue (there is an incompatibility between new ZFS kernel modules 
>> and old userland tools), but it will bite everyone using freebsd-update and 
>> ZFS.
>
> If we are talking about freebsd-update... It would be nice if freebsd-update 
> leave old kernel available in /boot/ as with source upgrade 
> (/boot/kernel.old) at least until second reboot (in case of upgrade), 
> because if new kernel failed to boot after first reboot, then the machine 
> become unbootable without some kind of LiveFS media.

This change was made in August, and I agree it was a very good idea:

   r196392 | simon | 2009-08-19 21:47:31 +0100 (Wed, 19 Aug 2009) | 17 lines

   Add support for backing up the old kernel when installing a new kernel
   using freebsd-update.  This applies to using freebsd-update in "upgrade
   mode" and normal freebsd-update on a security branch.

   The backup kernel will be written to /boot/kernel.old, if the directory
   does not exist, or the directory was created by freebsd-update in a
   previous backup.  Otherwise freebsd-update will generate a new directory
   name for use by the backup.  By default symbol files are not backed up
   to save diskspace and avoid filling up the root partition.

   This feature is fully configurable in the freebsd-update config file,
   but defaults to enabled.

   MFC after:      1 week (stable/7)
   Reviewed by:    cperciva
   Approved by:    re (kib)

Robert N M Watson
Computer Laboratory
University of Cambridge