Re: [Qemu-devel] [PATCH v4 00/11] convert savevm to use qapi and introduce qmp command

[Pavel Hrdina <phrdina@redhat.com>]

On 10.4.2013 10:18, Markus Armbruster wrote:
> Pavel Hrdina <phrdina@redhat.com> writes:
>
>> This patch series convert the savevm command into qapi and introduce QMP
>> command vm-snapshot-save.
>> It also rewrite error report for functions used by this command.
>>
>> The last patch introduce new functionality of savevm that you cannot override
>> existing snapshot without using 'force' parameter.
>>
>> If non-blocking behaviour of this command is required and we cannot wait
>> until live snapshots will be finished, I could improve this basic command
>> to be non-blocking.
>
> I had a couple of questions, but the code looks generally solid.  The
> most serious question is about the design of the QMP command.  We need
> to reach consensus there before we can make further progress.
>

I agree that the savevm needs to be modified.

The first thing what we should discuss is the use of name as tak or
id. I think that the best solution should be that we will have separate
arguments of both. We will use the 'name' argument to specify the tag
of a snapshot and we will add a new argument named 'id' to specify the
id of the snapshot.
There will be some restriction how to use them.
   - If you are creating new snapshot, you could use only the 'name'
     argument because the id will be generated.
   - If you want to overwrite an existing snapshot, you could specify
     the 'id' or the 'name' argument or both of them and also you will
     have to use the 'force' argument
   - I think that the 'name' argument don't need to be mandatory for QMP
     and also for HMP if we will generate the name.
   - We always return/print information about created snapshot that
     everyone knows which snapshot has been created.

The loadvm will use also both arguments and with this we will support
snapshots without tags, because you can specify that you want load
the snapshot by 'id'

Pavel