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Date: Tue, 3 Mar 2015 20:12:52 +0800
From: Wen Congyang <wency@cn.fujitsu.com>
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Subject: Re: [Qemu-devel] [RFC PATCH 01/14] docs: block replication's
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To: Fam Zheng <famz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Lai Jiangshan <laijs@cn.fujitsu.com>, Jiang Yunhong <yunhong.jiang@intel.com>, Dong Eddie <eddie.dong@intel.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, qemu devel <qemu-devel@nongnu.org>, Gonglei <arei.gonglei@huawei.com>, Stefan Hajnoczi <stefanha@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Yang Hongyang <yanghy@cn.fujitsu.com>, jsnow@redhat.com, zhanghailiang <zhang.zhanghailiang@huawei.com>

On 03/03/2015 03:59 PM, Fam Zheng wrote:
> On Tue, 03/03 15:53, Wen Congyang wrote:
>> I test qcow2_make_empty()'s performance. The result shows that it may
>> take about 100ms(normal sata disk). It is not acceptable for COLO. So
>> I think disk buff is necessary(just use it to replace qcow2).
> 
> Why not tmpfs or ramdisk?

I test it, and it only takes 2-3ms.

Thanks
Wen Congyang

> 
> Fam
> .
>