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Date: Tue, 1 Mar 2011 09:40:27 +0000
Message-ID: <AANLkTimMyCmy6yYJM6+5QdAt0DjCQq=WHE1iOwpJJHAq@mail.gmail.com>
Subject: Re: [Qemu-devel] Re: KVM call agenda for Jan 25
From: Stefan Hajnoczi <stefanha@gmail.com>
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To: Dushyant Bansal <cs5070214@cse.iitd.ac.in>
Cc: qemu-devel@nongnu.org

On Mon, Feb 28, 2011 at 8:41 PM, Dushyant Bansal
<cs5070214@cse.iitd.ac.in> wrote:
> On Sunday 27 February 2011 04:19 PM, Stefan Hajnoczi wrote:
>>
>> On Sat, Feb 26, 2011 at 9:50 PM, Dushyant Bansal
>> <cs5070214@cse.iitd.ac.in> =A0wrote:
>>>
>>> virtual size: 10G (10737418240 bytes)
>>> disk size: 569M
>>>
>>> convert-> =A0original
>>> time =A0 =A00m52.522s
>>>
>>> convert-> =A0modified (resultant disk size: 5.3G)
>>> time =A0 =A02m12.744s
>>>
>>> cp
>>> time =A0 =A00m51.724s (same disk size)
>>>
>>> -----------------------------------------------------------------------=
----
>>> virtual size: 10G (10737418240 bytes)
>>> disk size: 3.6G
>>>
>>> convert-> =A0original
>>> time =A0 =A01m52.249s
>>>
>>> convert-> =A0modified (resultant disk size: 7.1G)
>>> time =A0 =A03m2.891s
>>>
>>> cp
>>> time =A0 =A01m55.320s (same disk size)
>>>
>>> -----------------------------------------------------------------------=
----
>>> In these results, we can see that resultant disk size has increased.
>>>
>>
>> If I'm reading this correctly then qemu-img convert is within a few
>> seconds of cp(1) for you?
>>
>
> I have collected and attached some more time results for different
> operations on a 2.2G image.
> qemu-img convert is close to cp.
>
> qemu(modified):
> IO_BUF_SIZE =3D (2 * 1024 )
> if any sector is non-null, write all sectors

Nice that qemu-img convert isn't that far out by default on raw :).

About Google Summer of Code, I have posted my take on applying and
want to share that with you and qemu-devel:

http://blog.vmsplice.net/2011/03/advice-for-students-applying-to-google.htm=
l

Stefan