Re: [Qemu-devel] [Qemu-block] [PATCH COLO-Block v6 07/16] Add new block driver interface to connect/disconnect the remote target

[Dr. David Alan Gilbert]

* Wen Congyang (address@hidden) wrote:
> On 07/02/2015 02:42 AM, Dr. David Alan Gilbert wrote:
> > * Wen Congyang (address@hidden) wrote:
> >> On 07/01/2015 04:11 PM, Dr. David Alan Gilbert wrote:
> >>> * Wen Congyang (address@hidden) wrote:
> >>>> On 07/01/2015 03:01 AM, Dr. David Alan Gilbert wrote:
> >>>>> * Wen Congyang (address@hidden) wrote:
> >>>>>> On 06/27/2015 03:03 AM, Dr. David Alan Gilbert wrote:
> >>>>>
> >>>>> <snip>
> >>>>>
> >>>>>>> Ah, I hadn't realised you could do that; so do you just do:
> >>>>>>>
> >>>>>>> migrate_set_parameter colo on
> >>>>>>> migrate -d -b tcp:otherhhost:port
> >>>>>>>
> >>>>>>> How does the secondary know to feed that data straight into the disk 
> >>>>>>> without
> >>>>>>> recording all the old data into the hidden-disk ?
> >>>>>>
> >>>>>> hidden disk and active disk will be made empty when starting block 
> >>>>>> replication.
> >>>>>
> >>>>> Hmm, yes - I think I need to update to your current world; in the 
> >>>>> version
> >>>>> from the end of May, I get a 'error while loading state for instance 
> >>>>> 0x0 of device 'block''
> >>>>> if I try to use migrate -d -b 
> >>>>> (the bdrv_write fails)
> >>>>
> >>>> Can you give me both primary and secondary qemu's command? I think the 
> >>>> command line is wrong,
> >>>> and disk migration fails.
> >>>>
> >>>
> >>> Primary:
> >>>
> >>> ./try/bin/qemu-system-x86_64 -enable-kvm -nographic \
> >>>      -boot c -m 4096 -smp 4 -S \
> >>>      -name debug-threads=on -trace events=trace-file \
> >>>      -netdev tap,id=hn0,script=$PWD/ifup-prim,\
> >>> downscript=no,colo_script=$PWD/qemu/scripts/colo-proxy-script.sh,colo_nicname=em4
> >>>  \
> >>>      -device e1000,mac=9c:da:4d:1c:b5:89,id=net-pci0,netdev=hn0 \
> >>>      -drive if=virtio,driver=quorum,read-pattern=fifo,no-connect=on,\
> >>> cache=none,aio=native,\
> >>> children.0.file.filename=./bugzilla.raw,\
> >>> children.0.driver=raw,\
> >>> children.1.file.driver=nbd,\
> >>> children.1.file.host=ibpair,\
> >>> children.1.file.port=8889,\
> >>> children.1.file.export=colo1,\
> >>> children.1.driver=replication,\
> >>> children.1.mode=primary,\
> >>> children.1.ignore-errors=on
> >>
> >> Add id=nbd_target1 to primary disk option, and try it. Disk migration 
> >> needs the same id to sync
> >> the disk.
> > 
> > Thank you! That worked nicely.
> > The only odd thing was that the hidden disk on the secondary went upto ~2GB 
> > in size during
> > the disk copy; (This is still on the version you posted at the end of may).
> > I don't really understand why it was 2GB - the disk was 40GB, and qemu-img 
> > tells me that
> > 2.6GB of it were used.   Still, it would be good to avoid the overhead of 
> > going through
> > the hidden disk on the secondary for the initial replication.
> 
> Yes, I have fixed it in v7: starting backup job later.

Thanks, I'll try it.

Dave

> 
> Thanks
> Wen Congyang
> 
> > 
> > Dave
> > 
> >> Thanks
> >> Wen Congyang
> >>
> >>>
> >>>
> >>> Secondary:
> >>>
> >>> ./try/bin/qemu-system-x86_64 -enable-kvm -nographic \
> >>>      -boot c -m 4096 -smp 4 -S \
> >>>      -name debug-threads=on -trace events=trace-file \
> >>>      -netdev tap,id=hn0,script=$PWD/ifup-slave,\
> >>> downscript=no,colo_script=$PWD/qemu/scripts/colo-proxy-script.sh,colo_nicname=em4
> >>>  \
> >>>      -device e1000,mac=9c:da:4d:1c:b5:89,id=net-pci0,netdev=hn0 \
> >>>      -drive 
> >>> if=none,driver=raw,file=bugzilla.raw,id=nbd_target1,cache=none,aio=native 
> >>> \
> >>>      -drive 
> >>> if=virtio,driver=replication,mode=secondary,export=colo1,throttling.bps-total-max=70000000,\
> >>> file.file.filename=/run/colo-active-disk.qcow2,\
> >>> file.driver=qcow2,\
> >>> file.backing_reference.drive_id=nbd_target1,\
> >>> file.backing_reference.hidden-disk.file.filename=/run/colo-hidden-disk.qcow2,\
> >>> file.backing_reference.hidden-disk.driver=qcow2,\
> >>> file.backing_reference.hidden-disk.allow-write-backing-file=on \
> >>>      -incoming tcp:0:8888
> >>>
> >>>
> >>> Thanks,
> >>>
> >>> Dave
> >>>
> >>>>>>>> If the user uses mirror job, we don't cancel the mirror job now.
> >>>>>>>
> >>>>>>> It would be good to get it to work with mirror, that seems preferred 
> >>>>>>> these
> >>>>>>> days to the old block migration.
> >>>>>>
> >>>>>> In normal migration, is mirror job created and cancelled by libvirt?
> >>>>>
> >>>>> Yes, I think so; you should be able to turn on full logging on libvirt 
> >>>>> and
> >>>>> watch the qmp commands it sends.
> >>>>
> >>>> Supporting mirror job in my TODO list now. But I think we should focus 
> >>>> the basci function now.
> >>>>
> >>>> Thanks
> >>>> Wen Congyang
> >>>>
> >>>>>
> >>>>> Dave
> >>>>>
> >>>>> --
> >>>>> Dr. David Alan Gilbert / address@hidden / Manchester, UK
> >>>>> .
> >>>>>
> >>>>
> >>> --
> >>> Dr. David Alan Gilbert / address@hidden / Manchester, UK
> >>> .
> >>>
> >>
> > --
> > Dr. David Alan Gilbert / address@hidden / Manchester, UK
> > .
> > 
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK