Re: [Qemu-devel] question about live migration with storage

[Zhang Haoyu]

On 2015-01-15 17:11:49, Paolo Bonzini wrote:
> 
> On 15/01/2015 04:54, Zhang Haoyu wrote:
> >>>> > >> 2) Finer-grain control the parameters of block migration (dirty 
> >>>> > >> bitmap
> >>>> > >> granularity).
> >>>> > >>
> >>>> > >> 3) Block and RAM migration do not share the same socket and thus can
> >>>> > >> more easily be parallelized.
> >>>> > >>
> > drive_mirror job is done in main-thread,
> > then how to accept the qmp_migrate request while drive_mirror is performing?
> > If need to wait for the completion of drive_mirror,
> > how to implement the parallelization between block and ram migration?
> 
> drive_mirror runs in the background, using coroutines.
> 
I see, when waiting the completion of drive_mirror IO, the coroutine will be
switched back to main-thread to poll and process other events, like qmp request,
then after the IO completed, coroutine will be switched back in main-loop 
process, right?

Another question:
while starting to migrate storage, will the unused sector be allocated and 
transferred?
regarding the thin-provisioning qcow2 disk, will extra large IO requests be
performed, and more data be transferred for the unallocated clusters?

Thanks,
Zhang Haoyu
> Paolo