Re: rump is complete

[Alistair Crooks <agc%pkgsrc.org@localhost>]

On Tue, Mar 22, 2011 at 10:34:28AM +0000, Stephen Borrill wrote:
> On Tue, 22 Mar 2011, Christoph Egger wrote:
> [snip]
> >I'm also interested in how to use qcow images
> >to run qemu / xen guests.
> 
> That's probably more jmcneill's libvdisk stuff which uses pud(4) so that 
> a userland process can be used to manage a block device, e.g. a process 
> that understands .vhd files but allows them to be accessed in a similar 
> way to vnd(4). Similar to blktap AIUI. A couple of developers were looking 
> at his work, I'm not sure how far it got.

Possibly - qcow images are actually the other way around from what you'd
expect; they are like our fss(4) snapshots, in that they hold the original
blocks, while the file system image itself contains the changed blocks.
The snapshots created for vhd and vmdk (it's been a while, please correct
me if I'm wrong) work the other way around, holding the image at the time
the snapshot was taken. Well, it's not as simple as that, I think of them
more as REDO-logs, but you get the picture. Har.

I have added some embryonic stuff to jared's lib for it to use vmdk images,
but it's no more than that. If anyone wants to take this and run with it,
they're welcome - please feel free.

Best,
Alistair