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Date: Fri, 24 Apr 2015 10:16:45 +0800
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Subject: Re: [Qemu-devel] [PATCH COLO v3 01/14] docs: block replication's
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To: Fam Zheng <famz@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Yang Hongyang <yanghy@cn.fujitsu.com>, Lai Jiangshan <laijs@cn.fujitsu.com>, qemu block <qemu-block@nongnu.org>, armbru@redhat.com, jcody@redhat.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>, Max Reitz <mreitz@redhat.com>, zhanghailiang <zhang.zhanghailiang@huawei.com>

On 04/24/2015 10:01 AM, Fam Zheng wrote:
> On Thu, 04/23 14:23, Paolo Bonzini wrote:
>>
>>
>> On 23/04/2015 14:19, Dr. David Alan Gilbert wrote:
>>>>> So that means the bdrv_start_replication and bdrv_stop_replication
>>>>> callbacks are more or less redundant, at least on the primary?
>>>>>
>>>>> In fact, who calls them?  Certainly nothing in this patch set...
>>>>> :)
>>> In the main colo set (I'm looking at the February version) there
>>> are calls to them, the 'stop_replication' is called at failover time.
>>>
>>> Here is I think the later version:
>>> http://lists.nongnu.org/archive/html/qemu-devel/2015-03/msg05391.html
>>
>> I think the primary shouldn't do any I/O after failover (and the
>> secondary should close the NBD server) so it is probably okay to ignore
>> the removal for now.  Inserting the filter dynamically is probably
>> needed though.
> 
> Or maybe just enabling/disabling?

Hmm, after failover, the secondary qemu should become primary qemu, but we don't
know the nbd server's IP/port when we execute the secondary qemu. So we need
to inserting nbd client dynamically after failover.

Thanks
Wen Congyang

> 
> Fam
> .
>