Re: [Qemu-devel] [PATCH v2 0/6] external backup api

[Fam Zheng <famz@redhat.com>]

On Sat, 01/30 13:56, Vladimir Sementsov-Ogievskiy wrote:
> Hi all.
> 
> These series which aims to add external backup api. This is needed to allow
> backup software use our dirty bitmaps.
> 
> Vmware and Parallels Cloud Server have this feature.

What is the advantage of this appraoch over "drive-backup sync=incremental
..."?

> 
> There are three things are done:
> - add query-block-dirty-bitmap-ranges qmp command
> - add qmp commands for dirty-bitmap functions: create_successor, abdicate,
>   reclaim.
> - make create-successor command transaction-able
> 
> Then, external backup should be done like this:
> 
> 1.  qmp transaction {
>         external-snapshot
>         bitmap-create-successor
>     }
> 
> 2.  qmp query frozen bitmap, not acquiring aio context.

What do you do with the query response, read the snapshot image with an
external tool?

Fam

> 
> 3.  do external backup, using snapshot and bitmap
> 
> 
> 4.  if (success backup)
>         qmp bitmap-abdicate
>     else
>         qmp bitmap-reclaime
> 
> 5.  qmp merge snapshot
> 
> 
> v2: a lot of additions and changes, no sense to compare with v1
> 
> 
> Vladimir Sementsov-Ogievskiy (6):
>   block dirty bitmap: add next_zero function
>   qmp: add query-block-dirty-bitmap-ranges
>   iotests: test query-block-dirty-bitmap-ranges
>   qapi: add qmp commands for some dirty bitmap functions
>   qapi: make block-dirty-bitmap-create-successor transaction-able
>   iotests: test external backup api
> 
>  block/dirty-bitmap.c         |  60 ++++++++++++++++++++++
>  blockdev.c                   | 113 +++++++++++++++++++++++++++++++++++++++++
>  include/block/dirty-bitmap.h |   9 ++++
>  include/qemu/hbitmap.h       |   8 +++
>  qapi-schema.json             |   4 +-
>  qapi/block-core.json         |  90 +++++++++++++++++++++++++++++++++
>  qmp-commands.hx              | 118 +++++++++++++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/150       |  88 ++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/150.out   |  21 ++++++++
>  tests/qemu-iotests/151       |  77 ++++++++++++++++++++++++++++
>  tests/qemu-iotests/151.out   |   7 +++
>  tests/qemu-iotests/group     |   2 +
>  util/hbitmap.c               |  26 ++++++++++
>  13 files changed, 622 insertions(+), 1 deletion(-)
>  create mode 100755 tests/qemu-iotests/150
>  create mode 100644 tests/qemu-iotests/150.out
>  create mode 100755 tests/qemu-iotests/151
>  create mode 100644 tests/qemu-iotests/151.out
> 
> -- 
> 1.8.3.1
>