Re: [Qemu-devel] [PATCH] This patch adds a new block driver : iSCSI

[Orit Wasserman]

On Thu, 2011-09-15 at 14:58 +0200, Paolo Bonzini wrote:
> On 09/15/2011 02:34 PM, Orit Wasserman wrote:
> >> >  Then you need an iSCSI*target*  that understands qcow2, like qemu-nbd
> >> >  but for iSCSI... that's exactly the thing you were worried about
> >> >  implementing.
> >
> > Not really , this is just part of the target configuration.
> > For each file in the chain we create a lun in the target that is backed
> > by the file and we number the luns in chronological order (base is lun
> > 1) . you can look at a tgtd configuration here
> > http://wiki.qemu.org/Features/LiveBlockMigration#Example_single_base_master_image.
> 
> That's surely a weird way to use iSCSI. :)
:)
> It's clever, but I would call that shared storage, since you need to 
> share the details of the snapshot chain between the source and 
> destination, down to the file names.  We need a more precise nomenclature.
We store the parent base image inside the image (relative path). We can
reverse engineer it in the destination , start at the highest lun ,read
it's parent name , create a symbolic link to the parent (previous lun)
and so on ...

Orit
> Paolo