Re: [Qemu-devel] [PATCH] proto: add 'shift' extension.

[Denis V. Lunev]

On 09/27/2016 08:04 PM, Paolo Bonzini wrote:
>
> On 27/09/2016 15:28, Denis V. Lunev wrote:
>> On 09/27/2016 03:07 PM, Paolo Bonzini wrote:
>>> ----- Original Message -----
>>>> From: "Denis V. Lunev" <address@hidden>
>>>> To: "Paolo Bonzini" <address@hidden>
>>>> Cc: "Vladimir Sementsov-Ogievskiy" <address@hidden>, address@hidden, 
>>>> address@hidden,
>>>> address@hidden, address@hidden, address@hidden, address@hidden, 
>>>> address@hidden,
>>>> address@hidden
>>>> Sent: Tuesday, September 27, 2016 12:25:54 PM
>>>> Subject: Re: [PATCH] proto: add 'shift' extension.
>>>>
>>>> On 09/27/2016 01:15 PM, Paolo Bonzini wrote:
>>>>>> We could go in a different direction and export flag
>>>>>> 'has_zero_init' which will report that the storage is
>>>>>> initialized with all zeroes at the moment. In this
>>>>>> case mirroring code will not fall into this
>>>>>> branch.
>>>>> Why don't you add the zero_init flag to QEMU's NBD driver instead?
>>>> for all cases without knowing real backend on the server side?
>>>> I think this would be wrong.
>>> Add it to the command line, and leave it to libvirt or the user to
>>> pass "-drive file.driver=nbd,...,file.zero-init=on".
>> I have started with something very similar for 'drive-mirror' command.
>> We have added additional flag for this to improve migration speed
>> and this was rejected.
> You can add it through the filename path too, through a URI option
> "nbd://...?zero-init=on".
>
> Paolo
ha, cool idea! Thanks!

Den