Re: Re: [virtio-comment] About adding a new device type virtio-nvme

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Sun, Jan 29, 2023 at 11:32:43AM +0800, 侯英乐 wrote:
> Thu, 19 Jan 2023 06:42:49 -0500, Michael S. Tsirkin wrote:
> 
> >On Tue, Jan 17, 2023 at 11:01:37AM -0500, Stefan Hajnoczi wrote:
> 
> >> > The NVME technology and ecosystem are complete. However, in virtualization scenarios, NVME devices can only use PCIe pass-through . When NVME and virtio combine to connect to the vDPA ecosystem, live migration is supported.
> 
> >> >
> 
> >> >
> 
> >> > >Let's not forget that virtio-blk is widely used and new commands are
> 
> >> > >being added as needed. Which NVMe features are you missing in
> 
> >> > >virtio-blk?
> 
> >> >
> 
> >> > With the introduction of the concept of DPU, a large number of vendors are offloading virtual devices to hardware. The back-end of Virtio-blk does not support remote storage. Therefore, Virtio-Nvme-of can well combine the advantages of remote storage and virtio live migration
> 
> >>
> 
> >> virtio-blk is just a storage interface, whether that storage is local or
> 
> >> remote is up to the device implementation. The block device could be
> 
> >> located on Ceph, NFS, etc.
> 
> >>
> 
> >> Each virtio-blk device is a single block device. There is no
> 
> >> standardized management protocol in virtio-blk for connecting to remote
> 
> >> block devices. I'm aware of hardware virtio-blk devices that connect to
> 
> >> remote storage. Configuration is performed through an out-of-band
> 
> >> management interface.
> 
> >>
> 
> >> Maybe when you say virtio-blk doesn't support remote storage this is
> 
> >> what you mean?
> 
> >>
> 
> >> Stefan
> 
> >
> >侯英乐 you never answered this question.
> 
> 
> All the topics revolve around the scenario where the virtio device is offloading into the DPU.
> Virtio has a front-end and a back-end. What I mean is that I want to implement the back-end of Virtio-blk on the DPU.

You can do that today and the underlying storage can be remote.

Can you explain what you mean when you say virtio-blk doesn't support
remote storage?

Stefan

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