Re: [Qemu-devel] [RFC PATCH v2 00/23] COarse-grain LOck-stepping(COLO) Virtual Machines for Non-stop Service

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Hongyang Yang (yanghy@cn.fujitsu.com) wrote:
> Hi Dave,


> >For the COLO disk replication; are you talking here about 'local storage'
> >and treating it as 'internal state' or 'external state' (as described in the
> >first half of 4.4 in the original COLO paper)?
> 
> 'local storage' and 'internal state'. This is what later half of 4.4 said:
> 'COLO considers the state of local storage device as an internal s-
> tate of the guest, and snapshots the local storage state as part of the
> VM checkpoint, and plans to explore the other solution in future.'

Thanks for the clarification.

Dave

> 
> >
> >I know some groups would like to take advantage of facilities in the storage
> >layer to help; e.g. take snapshots/rollback etc - so I think it's best
> >to do (1) but make the interface clean so that other mechanisms could be added.
> >Similarly I guess things like scsi-xcopy might help for some people - I'm
> >not saying implement these, just if possible make an interface where it could
> >fit later.
> >
> >It's probably best to check with the QEMU storage guys that you can reuse
> >anything they have; there was a discussion a few weeks back where I cc'd
> >Fam, Stefan and Kevin in).
> >
> >Dave
> >
> >--
> >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> >.
> >
> 
> -- 
> Thanks,
> Yang.
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK