On Fri, Dec 19, 2014 at 02:12:55PM +0100, Klaus Aehlig wrote:
> 
> > +Proposed changes
> > +================
> > +
> > +Definitions
> > +-----------
> > +
> > +* All disks have exactly one *disk type*, which determines where and how 
> > the
> > +  disk can be stored. If the disk is transfered, the disk type remains
> > +  unchanged.
> 
> This is a bit misleading, as we usually use the term "disk type" to referr to
> the way the disk is built up, i.e., things like "drbd", "plain", and "file".
> However, already now we can specify which volume group a disk for an instance
> is to be taken from---and that is supposed to remain unchanged over instance
> moves. A typical use case for this already existing feature is to have two 
> volume
> groups formed of different physical disks, e.g., solid-state disk and hard 
> drives.
> 
> So, is this notion supposed to be "disk type" in the sense we use it for
> disk templates (then the assumptions that all providers of that disk type
> are equal does not hold, already now) or is it supposed to be an abstract
> name space supposed to take also into account how storage for that type is
> provided (then I'd prefere a name not easily confusable with the notion
> of disk type we already have)?

Ok, so we would need to determine the `StorageUnit` of a disk, which
contains exactly the information necessary. However it doesn't make
sense to talk about the storage unit of a disk (especially if it's not
assigned to a node yet), so I suggest *desired storage unit*.

This also changes the notion of a storage unit, because then
they can exist on different nodes. Either "storage unit of a
node", or "storage unit bin" as a description of the different storage
units present on a specific node?

>  
> 
> -- 
> Klaus Aehlig
> Google Germany GmbH, Dienerstr. 12, 80331 Muenchen
> Registergericht und -nummer: Hamburg, HRB 86891
> Sitz der Gesellschaft: Hamburg
> Geschaeftsfuehrer: Graham Law, Christine Elizabeth Flores

-- 
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80331 München

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