Re: [RFC 21/24] backup: move to block-copy

[Vladimir Sementsov-Ogievskiy]

15.11.2019 20:58, Eric Blake wrote:
> On 11/15/19 8:14 AM, Vladimir Sementsov-Ogievskiy wrote:
>> This brings async request handling and block-status driven chunk sizes
>> to backup out of the box, which improves backup performance.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
>> ---
> 
>> +++ b/qapi/block-core.json
>> @@ -1455,6 +1455,12 @@
>>   #                    above node specified by @drive. If this option is not 
>> given,
>>   #                    a node name is autogenerated. (Since: 4.2)
>>   #
>> +# @x-max-workers: maximum of parallel requests for static data backup. This
>> +#                 doesn't influence copy-before-write operations. (Since: 
>> 4.3)
>> +#
>> +# @x-max-chunk: maximum chunk length for static data backup. This doesn't
>> +#               influence copy-before-write operations. (Since: 4.3)
> 
> The next release is 5.0, not 4.3.
> 
> Is there a reason to keep these experimental for a while?  For example, are 
> there potential changes to the interface that might affect how it gets used?  
> Or should we drop the x- prefix and add this outright in 5.0?
> 

Hmm, I added these options to satisfy some very conservative iotests. Still, 
they may be meaningful for user too.

The only real doubt is that actually they are options of block-copy, not backup 
job. And to not finish up with adding such
parameters to each block-job, it may be better to combine them into a 
structure.. Or may be not.

-- 
Best regards,
Vladimir