[Thincrust-devel] packaging of sparse raw disk images

[David Lutterkort]

On Mon, 2008-11-17 at 08:52 -0500, Bryan Kearney wrote:
> Alan Pevec wrote:
> > 
> > virt-image XML has disk at use='scratch' which creates new empty disk image 
> > during VM instantiation,
> > but you still need ACE to mkfs, create mountpoint, fstab entry etc.
> 
> 
> I was thinking along the same lines.. that if you have a disk marked 
> "data" it would create a persistent disk at install.

That should work right now .. data and scratch should be handled the
same way when it comes to disk creation.

> But, that would assume that the appliance defines it internally.

Another option would be to extend the virt-image metadata so that you
can define partitions/fs/mountpoints for the disk and have virt-image
set that up; given the number of possibilities there, it would be a bear
to implement.

A better way would be for ace to ship some modules that let you
recognize and initialize empty disks.

> Looking at the ovf vman 
> spec[1] there is support for "empty" disks being sent, but no way to 
> distinguish between scatch and data. This would mean we would need to 
> pick a model for conversion (e.g. always assume data).

What are the semantics for 'empty' ? The difference behind scratch and
data is that data contains stuff that should be preserved across runs of
a VM, whereas scratch can be discarded and recreated when the VM reboots
- not that that is used by any of our tools right now.

David