[RFC] Remove requirement of alignment to track from MBR scheme

[Andriy Gapon]

on 25/05/2011 18:24 Marcel Moolenaar said the following:
> 
> On May 25, 2011, at 8:12 AM, Andriy Gapon wrote:
> 
>> on 24/05/2011 21:12 Marcel Moolenaar said the following:
>>> With respect to the creation:
>>>
>>> Since out synthesized geometry is not necessarily the same
>>> as other OSes, we could opt to synthesize a geometry that
>>> has a track size (= sectors/track) that is a multiple of 8
>>> (to play nice with 4K sectors), and/or take the stripe
>>> size of the underlying GEOM into account. This fundamentally
>>> doesn't change a thing for MBR, but has the side effect of
>>> achieving some of the goals *and* automatically works for
>>> EBR as well.
>>>
>>> Thus: rather than hack MBR and forgetting about EBR and other
>>> schemes, maybe we only have to tweak the geometry synthesis
>>> to give people what they want without going over board. 
>>
>> I don't think that currently we do synthesize any geometry in kernel.
>> I think that we just whatever BIOS/firmware/etc provides to us in some way.
> 
> Yes, we do. gpart makes sure that there's always a geometry
> and it adjusts the geometry based on information obtained
> from schemes. The geometry given by geom_disk (= ad or da)
> is typically the starting point. md does not have geometry
> information, causing certain tools to work less well.

OK.  I just haven't payed attention to that, sorry.

-- 
Andriy Gapon