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

[Wen Congyang <wency@cn.fujitsu.com>]

On 07/06/2015 05:42 PM, Dr. David Alan Gilbert wrote:
> * Wen Congyang (ghostwcy@gmail.com) wrote:
>> At 2015/7/3 23:30, Dr. David Alan Gilbert Wrote:
>>> * Wen Congyang (wency@cn.fujitsu.com) wrote:
>>>> Block replication is a very important feature which is used for
>>>> continuous checkpoints(for example: COLO).
>>>>
>>>> Usage:
>>>> Please refer to docs/block-replication.txt
>>>>
>>>> You can get the patch here:
>>>> https://github.com/wencongyang/qemu-colo/commits/block-replication-v7
>>>>
>>>> You can get ths patch with framework here:
>>>> https://github.com/wencongyang/qemu-colo/commits/colo_framework_v7.2
>>>
>>> Hi,
>>>   I seem to be having problems with the new listed syntax on the wiki;
>>> on the secondary I'm getting the error
>>>
>>>  Block format 'replication' used by device 'virtio0' doesn't support the option 'export'
>>>
>>> ./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
>>
>> Sorry, the option export is removed, because we use the qmp command
>> nbd-server-add to let a BB be NBD server.
> 
> If I remove the export=  the secondary starts, but then when I issue the child_add
> on the primary I get the error:
> 
> Server requires an export name
> 
> on the secondary I had done:
> 
> (qemu) nbd_server_start :8889
> (qemu) nbd_server_add -w colo1
> 
> Can you please confirm your exact command line and sequence needed with this 7.2 set please.

This is the child_add command that I used:

child_add disk1 child.driver=replication,child.mode=primary,child.file.host=$nbd_host,child.file.port=$nbd_port,child.file.export=colo1,child.file.driver=nbd,child.ignore-errors=on

I guess you remove export from this command too.

Thanks
Wen Congyang

> 
>>
>>> This is using 6fd6ce32 from the colo_framework_v7.2  tag.
>>>
>>> What have I missed?
>>>
>>> Dave
>>> P.S. the name 'file.backing.backing.backing_reference' is not nice!
>>
>> Which name is better? My native language is not English, so any such
>> suggestion is welcome.
> 
> My only problem is the way that 'backing' is repeated 3 times; that seems
> odd!
> 
> Dave
> 
>>
>> Thanks
>> Wen Congyang
>>
>>>
>>>>
>>>> TODO:
>>>> 1. Continuous block replication. It will be started after basic functions
>>>>    are accepted.
>>>>
>>>> Changs Log:
>>>> V7:
>>>> 1. Implement adding/removing quorum child. Remove the option non-connect.
>>>> 2. Simplify the backing refrence option according to Stefan Hajnoczi's suggestion
>>>> V6:
>>>> 1. Rebase to the newest qemu.
>>>> V5:
>>>> 1. Address the comments from Gong Lei
>>>> 2. Speed the failover up. The secondary vm can take over very quickly even
>>>>    if there are too many I/O requests.
>>>> V4:
>>>> 1. Introduce a new driver replication to avoid touch nbd and qcow2.
>>>> V3:
>>>> 1: use error_setg() instead of error_set()
>>>> 2. Add a new block job API
>>>> 3. Active disk, hidden disk and nbd target uses the same AioContext
>>>> 4. Add a testcase to test new hbitmap API
>>>> V2:
>>>> 1. Redesign the secondary qemu(use image-fleecing)
>>>> 2. Use Error objects to return error message
>>>> 3. Address the comments from Max Reitz and Eric Blake
>>>>
>>>>
>>>> Wen Congyang (17):
>>>>   Add new block driver interface to add/delete a BDS's child
>>>>   quorum: implement block driver interfaces add/delete a BDS's child
>>>>   hmp: add monitor command to add/remove a child
>>>>   introduce a new API qemu_opts_absorb_qdict_by_index()
>>>>   quorum: allow ignoring child errors
>>>>   introduce a new API to enable/disable attach device model
>>>>   introduce a new API to check if blk is attached
>>>>   block: make bdrv_put_ref_bh_schedule() as a public API
>>>>   Backup: clear all bitmap when doing block checkpoint
>>>>   allow writing to the backing file
>>>>   Allow creating backup jobs when opening BDS
>>>>   block: Allow references for backing files
>>>>   docs: block replication's description
>>>>   Add new block driver interfaces to control block replication
>>>>   skip nbd_target when starting block replication
>>>>   quorum: implement block driver interfaces for block replication
>>>>   Implement new driver for block replication
>>>>
>>>>  block.c                        | 198 +++++++++++++++++-
>>>>  block/Makefile.objs            |   3 +-
>>>>  block/backup.c                 |  13 ++
>>>>  block/block-backend.c          |  33 +++
>>>>  block/quorum.c                 | 244 ++++++++++++++++++++++-
>>>>  block/replication.c            | 443 +++++++++++++++++++++++++++++++++++++++++
>>>>  blockdev.c                     |  90 ++++++---
>>>>  blockjob.c                     |  10 +
>>>>  docs/block-replication.txt     | 179 +++++++++++++++++
>>>>  hmp-commands.hx                |  28 +++
>>>>  include/block/block.h          |  11 +
>>>>  include/block/block_int.h      |  19 ++
>>>>  include/block/blockjob.h       |  12 ++
>>>>  include/qemu/option.h          |   2 +
>>>>  include/sysemu/block-backend.h |   3 +
>>>>  include/sysemu/blockdev.h      |   2 +
>>>>  qapi/block.json                |  16 ++
>>>>  util/qemu-option.c             |  44 ++++
>>>>  18 files changed, 1303 insertions(+), 47 deletions(-)
>>>>  create mode 100644 block/replication.c
>>>>  create mode 100644 docs/block-replication.txt
>>>>
>>>> --
>>>> 2.4.3
>>>>
>>> --
>>> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>>>
>>>
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> .
>