Re: Looks like the arm 20220805 snapshots are still odd, so probably kern.geom.part.mbr.enforce_chs=0 was still in use

> On 2022-Aug-7, at 14:51, Dr. Rolf Jansen <freebsd-rj@cyclaero.com> wrote:
> 
>> Am 07.08.2022 um 16:50 schrieb Mark Millard <marklmi@yahoo.com>:
>> 
>> On 2022-Aug-7, at 12:32, Glen Barber <gjb@freebsd.org> wrote:
>> 
>>> Correct, it was set to “0” for these builds.
>>> 
>>> I honestly do not have any idea where the problems you are seeing are creeping in.
>>> 
>>> Should it be set back to “1”?  I’m not sure how to proceed otherwise.
>> 
>> My guess is that if the release/tools/arm.subr line:
>> 
>>             chroot ${CHROOTDIR} gpart add -t freebsd-ufs -a 64k ${mddev}s2
>> 
>> was instead (note the added -b use):
>> 
>>             chroot ${CHROOTDIR} gpart add -t freebsd-ufs -b 64k -a 64k ${mddev}s2
>> 
>> then the line:
>> 
>>             chroot ${CHROOTDIR} newfs -U -L rootfs /dev/${mddev}s2a
>> 
>> would work as expected and things would still be aligned:
>> no aliasing of BSD vs. freebsd-ufs. (In part this is by
>> prior steps already having achieved alignment of BSD.)
> 
> From a strict mathematical stand point of view, -a is not necessary when using -b with an aligned value.

"-a" controls more than the start offset: also the size.

QUOTE
               -a alignment  If specified, then the gpart utility tries to
                             align start offset and partition size to be
                             multiple of alignment value.
END QUOTE

I expect your statement would at most apply to the start offset, not to
everything "-a" does.

> Personally I don’t use the -a option of gpart anymore since it started to do funny magics in front of face. If I remember correct, gpart of the FreeBSD 9.x-RELEASES was still OK (or was it 8?). Nowadays, I align all my storage media by employing -b with a reasonable value.
> 

I've no clue of the specifics that you are referencing and so can not check.

===
Mark Millard
marklmi at yahoo.com