* Wen Congyang (we...@cn.fujitsu.com) wrote: > On 07/08/2015 11:49 PM, Michael R. Hines wrote: > > On 07/07/2015 08:38 PM, Wen Congyang wrote: > >> On 07/08/2015 12:56 AM, Michael R. Hines wrote: > >>> On 07/07/2015 04:23 AM, Paolo Bonzini wrote: > >>>> On 07/07/2015 11:13, Dr. David Alan Gilbert wrote: > >>>>>>> This log is very stange. The NBD client connects to NBD server, and > >>>>>>> NBD server wants to read data > >>>>>>> from NBD client, but reading fails. It seems that the connection is > >>>>>>> closed unexpectedly. Can you > >>>>>>> give me more log and how do you use it? > >>>>> That was the same failure I was getting. I think it's that the NBD > >>>>> server and client are in different > >>>>> modes, with one of them expecting the export. > >>>> nbd_server_add always expects the export. > >>>> > >>>> Paolo > >>>> > >>> OK, Wen, so your wiki finally does reflect this, but now we're back to > >>> the "export not found error". > >>> > >>> Again, here's the exact command line: > >>> > >>> 1. First on the secondary VM: > >>> > >>> qemu-system-x86_64 .........snip........... -drive > >>> if=none,driver=qcow2,file=foo.qcow2,id=mc1,cache=none,aio=native -drive > >>> if=virtio,driver=replication,mode=secondary,throttling.bps-total-max=70000000,file.file.filename=active_disk.qcow2,file.driver=qcow2,file.backing.file.filename=hidden_disk.qcow2,file.backing.driver=qcow2,file.backing.allow-write-backing-file=on,file.backing.backing.backing_reference=mc1 > >>> > >>> 2. Then, then HMP commands: > >>> > >>> nbd_server_start 0:6262 > >>> nbd_server_add -w mc1 > >>> > >>> 3. Then the primary VM: > >>> > >>> qemu-system-x86_64 .........snip........... -drive > >>> if=virtio,driver=quorum,read-pattern=fifo,no-connect=on,children.0.file.filename=bar.qcow2,children.0.driver=qcow2,children.1.file.driver=nbd,children.1.file.host=127.0.0.1,children.1.file.port=6262,children.1.driver=replication,children.1.mode=primary,children.1.ignore-errors=on > >>> > >>> With the error: Server requires an export name > >>> > >>> *but*, your wiki has no export name on the primary VM size, so I added > >>> the export name back which is on your old wiki: > >>> > >>> qemu-system-x86_64 .........snip........... -drive > >>> if=virtio,driver=quorum,read-pattern=fifo,no-connect=on,children.0.file.filename=bar.qcow2,children.0.driver=qcow2,children.1.file.driver=nbd,children.1.file.export=mc1,children.1.file.host=127.0.0.1,children.1.file.port=6262,children.1.driver=replication,children.1.mode=primary,children.1.ignore-errors=on: > >>> Failed to read export length > >>> > >> Hmm, I think you use v7 version. Is it right? > >> In this version, the correct useage for primary qemu is: > >> 1. qemu-system-x86_64 .........snip........... -drive > >> if=virtio,driver=quorum,read-pattern=fifo,id=disk1, > >> > >> children.0.file.filename=bar.qcow2,children.0.driver=qcow2, > >> > >> Then run hmp monitor command(It should be run after you run nbd_server_add > >> in the secondary 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 > >> > >> Thanks > >> Wen Congyang > >> > >>> And server now says: > >>> > >>> nbd.c:nbd_handle_export_name():L416: export not found > >>> nbd.c:nbd_send_negotiate():L562: option negotiation failed > >>> > >>> . > >>> > >> > > > > OK, I'm totally confused at this point. =) > > > > Maybe it would be easier to just wait for your next clean patchset + > > documentation which is all consistent with each other. > > 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. Dave > > Thanks > Wen Congyang > > > > > - Michael > > > > . > > > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK