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Date: Wed, 11 Mar 2015 14:44:08 +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?

Another problem:
After failover, secondary write request will be written in (active disk)?
It is better to write request to (nbd target). Is there any feature can
be reused to implement it?

Thanks
Wen Congyang

> 
> Fam
> .
>