Re: [Qemu-devel] tcmu-runner and QEMU

[Benoît Canet]

The Wednesday 03 Sep 2014 à 14:11:59 (+0100), Stefan Hajnoczi wrote :
> On Tue, Sep 02, 2014 at 05:20:55PM -0700, Andy Grover wrote:
> > On 09/02/2014 02:25 AM, Stefan Hajnoczi wrote:
> > > The qemu-lio tool would live in the QEMU codebase and reuse all the
> > > infrastructure.  For example, it could include a QMP monitor just like
> > > the one you are adding to qemu-nbd.
> > 
> > Benoit and I talked a little about QMP on another part of the thread... I
> > said I didn't think we needed a QMP monitor in qemu-lio-tcmu, but let me
> > spin up on qemu a little more and I'll be able to speak more intelligently.
> 
> The QEMU block layer has useful features that are available as QMP
> commands:
> 
> For example, the drive-mirror QMP command copies a disk image to a new
> location while still servicing I/O requests.  This is used when an
> administrator needs to migrate disk images to a new file system or
> storage devices without downtime.
> 
> There are other commands for snapshots and backup which are issued via
> QMP.
> 
> It might even make sense to make the tcmu interface available at
> run-time in QEMU like the run-time NBD server.  This allows you to get
> at read-only point-in-time snapshots while the guest is accessing the
> disk.  See the nbd-server-start command in qapi/block.json.
> 
> Stefan

Andy: ping

I hope we didn't scaried you with our monster block backend and it's
associated QMP socket ;)