Re: [Qemu-devel] [PATCH v3 0/9] block: generic image streaming

[Yibin Shen]

On Tue, Dec 13, 2011 at 11:18 PM, Stefan Hajnoczi <address@hidden> wrote:
> On Tue, Dec 13, 2011 at 2:12 PM, Yibin Shen <address@hidden> wrote:
>> all these patches looks good to me except one thing,
>> when I run a "qemu-img commit" command,
>> seems entire image(from start to end sector) will be write to the backing 
>> file,
>> I think what we really need is to commit only dirty sectors.
>> also maybe we can use a writeback mechanism alternaively.
>
> This series does not affect the behavior of "qemu-img commit".
>
> Are you suggesting a new feature?  Please explain a little more.
yes , I suggest a new feature,

in some situation, we need to commit data in qed image to backing file.
in old days ,people without copy-on-read, they only have copy-on-write,
so 'qemu-img commit' commit all exsits data to backing file is rational.

but with copy-on-read or image streaming,
which means most data in the image may be identical with backing file,
so commit entire image is a redundant operation.

can we record the dirty bitmap for data differ from backing file,
then in a commit operation, we only need to handle minimum data.

thanks
>
> Stefan
>

________________________________

This email (including any attachments) is confidential and may be legally 
privileged. If you received this email in error, please delete it immediately 
and do not copy it or use it for any purpose or disclose its contents to any 
other person. Thank you.

本电邮(包括任何附件)可能含有机密资料并受法律保护。如您不是正确的收件人，请您立即删除本邮件。请不要将本电邮进行复制并用作任何其他用途、或透露本邮件之内容。谢谢。