svn commit: r264378 - head/sys/geom/part

[John Baldwin]

On 4/12/14 1:28 PM, Marcel Moolenaar wrote:
> Author: marcel
> Date: Sat Apr 12 20:28:39 2014
> New Revision: 264378
> URL: http://svnweb.freebsd.org/changeset/base/264378
> 
> Log:
>   Align and round the partitionable disk space to 4K by default.
>   Since this would also apply when recovering, make sure not to
>   align or round when that would have a partition fall outside
>   the partitionable area.

This needs a way to be overridden.  If you have a machine installed with a
layout created prior to this change (e.g. a zpool mirror or RAID or some
other mirror or RAID), you can no longer create a matching partition since
the starting sector is now always 40 instead of 34 and the partition size
won't match.  Also, while we may want to create sane layouts by default, we
should probably always provide a way to create less-sane layouts that are
still conformant to the spec.  I do wonder if this kind of default
preference shouldn't belong in the userspace gpart tool rather than the
kernel and the kernel should create any compliant layout as requested by
userland instead.

jpaetzel@ just ran into this case where he can't replace a failed disk in a
system running 12 that was first formatted on 10, so it's not academic.

-- 
John Baldwin