Re: [CFC/CFT] large changes in the loader(8) code

On Wednesday, June 27, 2012 1:45:35 pm Marcel Moolenaar wrote:
> 
> On Jun 26, 2012, at 2:43 PM, Pawel Jakub Dawidek wrote:
> > 
> > As for sharing disk with other OS. If you share the disk with OS that
> > doesn't support gmirror, you shouldn't use gmirror in the first place.
> > You probably want to use only formats that are recognized by all your
> > OSes.
> 
> This statement is ridicuous by virtue of not being in touch with
> reality and by making gmirror useless for such wide range of cases
> that one can question why we have it at all.
> 
> Put differently: a mirroring class is a fairly basic and useful thing
> to have. Limiting it's use is nothing but artificial and follows from
> having to use the underlying provider to store metadata. This then
> changes the view of the underlying providing to consumers above gmirror
> in a way that makes the presence or absence of gmirror visible.
> Solving the visibility problem makes gmirror useful all the time.
> I see that as a better way of looking at it than simply blurting out
> that you shouldn't use gmirror when certain awkward and artifical
> conditions apply.

I'm not sure we can force gmirror to be anything except FreeBSD-specific,
but it would be nice to not make non-standard GPT tables while we are at it.

The reason the metadata for things like Intel's onboard SATA RAID does work
ok is because the metadata format is enforced by the vendor, so it is
reasonable to assume that metadata format will work across other OS's.

Anyway, I've said my piece and will let the matter drop from my end at this
point.

-- 
John Baldwin