I looked through the code with a colleague, apparently the code to 
increase object counters is not executed with ceph as backend. Is that 
assumption correct? Would be interesting to know for which backends 
that would actually increase per backup.

Zitat von Eugen Block <eblock@nde.ag>:

> I see the same for Wallaby, object_count is always 0.
>
> Zitat von Eugen Block <eblock@nde.ag>:
>
>> Hi,
>>
>> I don't see an object_count > 0 for all incremental backups or the 
>> full backup. I tried both with a "full" volume (from image) as well 
>> as en empty volume, put a filesystem on it and copied tiny files 
>> onto it. This is the result:
>>
>> controller02:~ # openstack volume backup list
>> +--------------------------------------+--------------+-------------+-----------+------+
>> | ID                                   | Name         | Description 
>> | Status    | Size |
>> +--------------------------------------+--------------+-------------+-----------+------+
>> | a8a448e7-8bfd-46e3-81bf-3b1d607893e7 | inc-backup2  | None         
>> | available |    4 |
>> | 3d11faa0-d67c-432d-afb1-ff44f6a3b4a7 | inc-backup1  | None         
>> | available |    4 |
>> | 125c23cd-a5e8-4a7a-b59a-015d0bc5902c | full-backup1 | None         
>> | available |    4 |
>> +--------------------------------------+--------------+-------------+-----------+------+
>>
>> controller02:~ # for i in `openstack volume backup list -c ID -f 
>> value`; do openstack volume backup show $i -c id -c is_incremental 
>> -c object_count -f value; done
>> a8a448e7-8bfd-46e3-81bf-3b1d607893e7
>> True
>>
>> 3d11faa0-d67c-432d-afb1-ff44f6a3b4a7
>> True
>>
>> 125c23cd-a5e8-4a7a-b59a-015d0bc5902c
>> False
>>
>>
>> This is still Victoria, though, I think I have a Wallaby test 
>> installation, I'll try that as well. In which case should 
>> object_count be > 0? All my installations have ceph as storage 
>> backend.
>>
>> Thanks,
>> Eugen
>>
>> Zitat von Masayuki Igawa <masayuki.igawa@gmail.com>:
>>
>>> Hi Satish,
>>>
>>>> Whenever I take incremental backup it shows a similar size of original
>>>> volume. Technically It should be smaller. Question is does ceph support
>>>> incremental backup with cinder?
>>>
>>> IIUC, it would be expected behavior. According to the API Doc[1],
>>> "size" is "The size of the volume, in gibibytes (GiB)."
>>> So, it's not the actual size of the snapshot itself.
>>>
>>> What about the "object_count" of "openstack volume backup show" output?
>>> The incremental's one should be zero or less than the full backup at least?
>>>
>>> [1] 
>>> https://docs.openstack.org/api-ref/block-storage/v3/?expanded=show-backup-detail-detail,list-backups-with-detail-detail#id428
>>>
>>> -- Masayuki Igawa
>>>
>>> On Wed, May 17, 2023, at 03:51, Satish Patel wrote:
>>>> Folks,
>>>>
>>>> I have ceph storage for my openstack and configure cinder-volume and
>>>> cinder-backup service for my disaster solution. I am trying to use the
>>>> cinder-backup incremental option to save storage space but somehow It
>>>> doesn't work the way it should work.
>>>>
>>>> Whenever I take incremental backup it shows a similar size of original
>>>> volume. Technically It should be smaller. Question is does ceph support
>>>> incremental backup with cinder?
>>>>
>>>> I am running a Yoga release.
>>>>
>>>> $ openstack volume list
>>>> +--------------------------------------+------------+------------+------+-------------------------------------+
>>>> | ID                                   | Name       | Status     | Size
>>>> | Attached to                         |
>>>> +--------------------------------------+------------+------------+------+-------------------------------------+
>>>> | 285a49a6-0e03-49e5-abf1-1c1efbfeb5f2 | spatel-vol | backing-up |   10
>>>> | Attached to spatel-foo on /dev/sdc  |
>>>> +--------------------------------------+------------+------------+------+-------------------------------------+
>>>>
>>>> ### Create full backup
>>>> $ openstack volume backup create --name spatel-vol-backup 
>>>> spatel-vol --force
>>>> +-------+--------------------------------------+
>>>> | Field | Value                                |
>>>> +-------+--------------------------------------+
>>>> | id    | 4351d9d3-85fa-4cd5-b21d-619b3385aefc |
>>>> | name  | spatel-vol-backup                    |
>>>> +-------+--------------------------------------+
>>>>
>>>> ### Create incremental
>>>> $ openstack volume backup create --name spatel-vol-backup-1
>>>> --incremental --force spatel-vol
>>>> +-------+--------------------------------------+
>>>> | Field | Value                                |
>>>> +-------+--------------------------------------+
>>>> | id    | 294b58af-771b-4a9f-bb7b-c37a4f84d678 |
>>>> | name  | spatel-vol-backup-1                  |
>>>> +-------+--------------------------------------+
>>>>
>>>> $ openstack volume backup list
>>>> +--------------------------------------+---------------------+-------------+-----------+------+
>>>> | ID                                   | Name                |
>>>> Description | Status    | Size |
>>>> +--------------------------------------+---------------------+-------------+-----------+------+
>>>> | 294b58af-771b-4a9f-bb7b-c37a4f84d678 | spatel-vol-backup-1 | None
>>>>  | available |   10 |
>>>> | 4351d9d3-85fa-4cd5-b21d-619b3385aefc | spatel-vol-backup   | None
>>>>  | available |   10 |
>>>> +--------------------------------------+---------------------+-------------+-----------+------+
>>>> My incremental backup still shows 10G size which should be lower
>>>> compared to the first backup.