Re: [Qemu-devel] block-stream/drive-mirror and default bandwidth

[Stefan Hajnoczi]

On Tue, Apr 17, 2012 at 1:14 PM, Eric Blake <address@hidden> wrote:
> On 04/17/2012 03:20 AM, Stefan Hajnoczi wrote:
>> I think it's cleanest to support block-job-set-speed even when no job
>> is running.  The speed will be used as the default value when a job is
>> started.  This poses the question of what happens if the job does not
>> do throttling or cannot support the value for some reason - does
>> creation fail until block-job-set-speed is set to 0 or a valid value
>> again, or do we allow it but silently perform no throttling?
>
> I'd prefer failure for any request for an out-of-range speed, and I like
> the idea of always letting the user set the speed, even when a job is
> not already running.  Am I correct that only one job can run at a time,
> and therefore, the speed can be a property associated with the
> BlockDevice as a whole, rather than only a property associated with each
> individual job?

Yes, the current design is 1 block job per device.

Stefan