Re: [Qemu-devel] [PATCH COLO-BLOCK v7 00/17] Block replication for continuous checkpoints

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

* Wen Congyang (wency@cn.fujitsu.com) wrote:
> On 07/09/2015 06:37 PM, Dr. David Alan Gilbert wrote:
> > * Wen Congyang (wency@cn.fujitsu.com) wrote:
> >> On 07/09/2015 05:16 PM, Dr. David Alan Gilbert wrote:
> >>> * Wen Congyang (wency@cn.fujitsu.com) wrote:
> >>>
> >>>>>> I have sent the v8. But the usage is not changed. You can setup the environment according to the wiki.
> >>>>>> When we open nbd client, we need to connect to the nbd server. So I introduce a new command child_add to add NBD client
> >>>>>> as a quorum child when the nbd server is ready.
> >>>>>>
> >>>>>> The nbd server is ready after you run the following command:
> >>>>>> nbd_server_start 0:6262 # the secondary qemu will listen to host:port
> >>>>>> nbd_server_add -w mc1   # the NBD server will know this disk is used as NBD server. The export name is its id wc1.
> >>>>>>                         # -w means we allow to write to this disk.
> >>>>>>
> >>>>>> Then you can run the following command in the primary qemu:
> >>>>>> child_add disk1 child.driver=replication,child.mode=primary,child.file.host=127.0.0.1,child.file.port=6262,child.file.export=mc1,child.file.driver=nbd,child.ignore-errors=on
> >>>>>>
> >>>>>> After this monitor command, nbd client has connected to the nbd server.
> >>>>>
> >>>>> Ah! The 'child.file.export=mc1' wasn't there previously; I see Yang added that to the wiki yesterday;
> >>>>> that probably explains the problem that we've been having.
> >>>>
> >>>> Sorry for this mistake.
> >>>
> >>> OK, so this is working for me (with the 7.2 world).   What isn't working in this setup is migrate -b, I get:
> >>>
> >>> (qemu) Receiving block device images
> >>> Error unknown block device disk1
> >>> qemu-system-x86_64: error while loading state section id 1(block)
> >>> qemu-system-x86_64: load of migration failed: Invalid argument
> >>>
> >>> Can you explain the id=disk1 on the master side?
> >>
> >> Can you give me the command line? I think the id in primary and secondary qemu is not same.
> > 
> > Sure, 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 \
> >      -device virtio-rng-pci \
> >      -drive if=virtio,id=disk1,driver=quorum,read-pattern=fifo,\
> 
> If you want to use block migration, set the id to colo1

OK, does it make sense to always make it colo1 rather than having the 'disk1' and 'colo1' names?

> > cache=none,aio=native,\
> > children.0.file.filename=./bugzilla.raw,\
> > children.0.driver=raw
> > 
> > Sure, secondary:
> > 
> > TMPDISKS=/run
> > qemu-img create -f qcow2 $TMPDISKS/colo-hidden-disk.qcow2 40G
> > qemu-img create -f qcow2 $TMPDISKS/colo-active-disk.qcow2 40G
> > 
> > ./try/bin/qemu-system-x86_64 -enable-kvm -nographic \
> >      -boot c -m 4096 -smp 4 -S \
> >      -name debug-threads=on -trace events=trace-file \
> >      -netdev tap,id=hn0,script=$PWD/ifup-slave,\
> > downscript=no,colo_script=$PWD/qemu/scripts/colo-proxy-script.sh,colo_nicname=em4 \
> >      -device e1000,mac=9c:da:4d:1c:b5:89,id=net-pci0,netdev=hn0 \
> >      -device virtio-rng-pci \
> >      -drive if=none,driver=raw,file=/home/localvms/bugzilla.raw,id=colo1,cache=none,aio=native \
> >      -drive if=virtio,driver=replication,mode=secondary,export=colo1,throttling.bps-total-max=70000000,\
> > file.file.filename=$TMPDISKS/colo-active-disk.qcow2,\
> > file.driver=qcow2,\
> > file.backing.file.filename=$TMPDISKS/colo-hidden-disk.qcow2,\
> > file.backing.driver=qcow2,\
> > file.backing.backing.backing_reference=colo1,\
> > file.backing.allow-write-backing-file=on \
> >      -incoming tcp:0:8888
> > 
> > 
> > Secondary:
> >    nbd_server_start :8889
> >    nbd_server_add -w colo1
> > 
> > primary:
> > 
> > child_add disk1 child.driver=replication,child.mode=primary,child.file.host=ibpair,child.file.port=8889,child.file.export=colo1,child.file.driver=nbd,child.ignore-errors=on
> 
> here, it is child_add colo1 ....
> 
> > (qemu) migrate_set_capability colo on
> > (qemu) migrate -d -b tcp:ibpair:8888
> > 
> > 
> > note the 'id=disk1' in the primary is shown in your wiki.
> 
> IIRC, the default id is diskx, x is 1, 2, 3...

OK, using the colo1 in both those places that works (this is in the 7.2 world)
and the RAM disk size now doesn't grow in the -b block migrate.

Dave

> 
> Thanks
> Wen Congyang
> 
> > 
> > Dave
> > 
> >  Thanks
> >> Wen Congyang
> >>
> >>>
> >>> Dave
> >>>
> >>>>
> >>>> Thanks
> >>>> Wen Congyang
> >>>>
> >>>>>
> >>>>> Dave
> >>>>>
> >>>>>>
> >>>>>> Thanks
> >>>>>> Wen Congyang
> >>>>>>
> >>>>>>>
> >>>>>>> - Michael
> >>>>>>>
> >>>>>>> .
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>> --
> >>>>> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> >>>>> .
> >>>>>
> >>>>
> >>> --
> >>> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> >>> .
> >>>
> >>
> >>
> > --
> > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> > .
> > 
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK