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

[Dr. David Alan Gilbert]

* Wen Congyang (address@hidden) wrote:
> On 07/09/2015 05:16 PM, Dr. David Alan Gilbert wrote:
> > * Wen Congyang (address@hidden) 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,\
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
(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.

Dave

 Thanks
> Wen Congyang
> 
> > 
> > Dave
> > 
> >>
> >> Thanks
> >> Wen Congyang
> >>
> >>>
> >>> Dave
> >>>
> >>>>
> >>>> Thanks
> >>>> Wen Congyang
> >>>>
> >>>>>
> >>>>> - Michael
> >>>>>
> >>>>> .
> >>>>>
> >>>>
> >>>>
> >>> --
> >>> Dr. David Alan Gilbert / address@hidden / Manchester, UK
> >>> .
> >>>
> >>
> > --
> > Dr. David Alan Gilbert / address@hidden / Manchester, UK
> > .
> > 
> 
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK