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

[Dr. David Alan Gilbert]

* Wen Congyang (address@hidden) 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

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!

> 
> 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 / address@hidden / Manchester, UK