boot0cfg on does not set default selection on gmirror device

[Ian Smith]

On Sun, 23 Oct 2016 15:53:59 +0200, Patrick M. Hausen wrote:
 > > Am 22.10.2016 um 05:36 schrieb Ian Smith <smithi at nimnet.asn.au>:
 > > [...]
 > > I wonder two things:
 > > 
 > > Do 'boot0cfg -v ada0' and 'boot0cfg -v ada1' both report the same?

Summary: yes, both equally wrong!

 > > Might it work properly if you upgraded the boot sectors to version 2, 
 > > which is what you should get if you reinstall from current boot0cfg, 
 > > presumably without touching the MBR data, but you'll have backups ..
 > 
 > Well ...
 > 
 > root at hd45:~ # boot0cfg -B mirror/m0
 > root at hd45:~ # boot0cfg -s 2 mirror/m0
 > root at hd45:~ # boot0cfg -v mirror/m0
 > #   flag     start chs   type       end chs       offset         size
 > 1   0x80      1:  0: 1   0xa5   1022:254:63        16065     16418430
 > 2   0x00   1023:  0: 1   0xa5   1020:254:63     16434495     16418430
 > 3   0x00   1021:  0: 1   0xa5    768:254:63     32852925   1920667140
 > 
 > version=2.0  drive=0x80  mask=0xf  ticks=182  bell=# (0x23)
 > options=packet,update,nosetdrv
 > volume serial ID b100-808f
 > default_selection=F2 (Slice 2)
 > 
 > root at hd45:~ # boot0cfg -v ada0
 > [...]
 > default_selection=F2 (Slice 2)
 > 
 > root at hd45:~ # boot0cfg -v ada1
 > [...]
 > default_selection=F2 (Slice 2)
 > 
 > Revert the change:
 > 
 > root at hd45:~ # boot0cfg -s 1 mirror/m0
 > root at hd45:~ # boot0cfg -v  mirror/m0
 > [...]
 > default_selection=F1 (Slice 1)
 > 
 > 
 > That did it! These machines have been in production for some time
 > starting with FreeBSD 8.x and have been upgraded via NanoBSD style
 > dd followed by reboot all the time up to 10.3, now. Hence I never touched
 > the bootcode.

Glad that one of my wild ill-informed wonderings was on target, and that 
gmirror is off the hook.

 > Actual reboot of this production machine in two weeks when we run our
 > regular updates. But I expect that to "just work".

Warner expected the existing boot0cfg code to "just work" too.  And it 
does, except that the upgrades to it failed to include a method to fix 
existing installations retrospectively!

cheers, Ian