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

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

On 03.02.2016 14:02, Fam Zheng wrote:
> On Wed, 02/03 13:57, Vladimir Sementsov-Ogievskiy wrote:
>> On 03.02.2016 11:14, Fam Zheng wrote:
>>> 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
>>> ..."?
>> Hmm, you are asking about advantage of external backup over
>> internal? It depends on external backup tool.
> I'm asking why the tool can't use drive-backup to achieve what you want. They
> seem very comparable.

drive-backup has limited range of maintained by qemu targets.. Third 
party tool uses its own internal targets. If we use drvie-backup there 
will be two copies instead of one: from qemu to drive-backup produced 
backup and then to internal target in third-party tool.

>
> Fam
>
>>>> 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?
>> Yes. Alternatively, image fleecing may be used instead of snapshot.
>>
>>> 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
>>>>
>>
>> -- 
>> Best regards,
>> Vladimir
>>


-- 
Best regards,
Vladimir