Indeed, just checked what is happening on the backing level:

before removing snapshot I have snapshot chain like:

aaa <-- snap1 <-- bbb

where `snap1` is snapshot of `aaa`, and `bbb` is snapshot of `snap1`

but after removing `snap1` from the linstor I have two fully separated
resources: `aaa` and `bbb`, where `bbb` have no origin anymore and
does not referenced to `aaa` anymore.

- kvaps

On Sun, May 26, 2019 at 10:43 AM Gianni Milo <[email protected]> wrote:
>
> Don't think it's a bug. In my setup I'm using ZFS as storage backend. When 
> repeating steps you described, ZFS complains and it does not delete the 
> snapshot, as the newly created clone depends on it. This by it's turn 
> propagates above to the LINSTOR layer, which eventually aborts the action.
> In the case you are using LVMThin, I think lvm *does* allow deleting the 
> snapshot, since it works differently than ZFS in this matter (data from the 
> deleted snapshot is automatically merged into the newly created volume, so 
> there's no dependency between them). You can verify if this is the case by 
> doing same tests directly on the lvm layer. In any case LINSTOR relies on 
> storage backend utils output and it does not by default prevent snapshot 
> removal.
>
>
> On Sun, 26 May 2019 at 00:49, kvaps <[email protected]> wrote:
>>
>> Hi
>>
>> I have a question and I can't fully determine is that bug or not.
>>
>> Example I have image A:
>>
>> linstor rd c A
>> linstor vd c aaa 1G
>> linstor r c aaa --auto-place 2
>>
>> now I can create new snapshot:
>>
>> linstor s c aaa snap1
>>
>> and deploy new resource from this snapshot:
>>
>> linstor rd c bbb
>> linstor s vd rst --from-resource aaa --from-snapshot snap1 --to-resource bbb
>> linstor s r rst --from-resource aaa --from-snapshot snap1 --to-resource bbb
>>
>> after that I can remove the snapshot:
>>
>> linstor s d aaa snap1
>>
>> Is that ok? Shouldn't it throw an error due having childrens?
>>
>>
>> - kvaps
>> _______________________________________________
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>> [email protected]
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