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

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

* 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 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