Re: [Qemu-devel] [Qemu-block] [PATCH COLO-Block v6 07/16] Add new block driver interface to connect/disconnect the remote target

From: Wen Congyang <wency@cn.fujitsu.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Fam Zheng <famz@redhat.com>,
	Wen Congyang <ghostwcy@gmail.com>,
	qemu block <qemu-block@nongnu.org>,
	Stefan Hajnoczi <stefanha@gmail.com>,
	Jiang Yunhong <yunhong.jiang@intel.com>,
	Dong Eddie <eddie.dong@intel.com>,
	qemu devel <qemu-devel@nongnu.org>, Max Reitz <mreitz@redhat.com>,
	Lai Jiangshan <laijs@cn.fujitsu.com>,
	Gonglei <arei.gonglei@huawei.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Yang Hongyang <yanghy@cn.fujitsu.com>,
	zhanghailiang <zhang.zhanghailiang@huawei.com>
Subject: Re: [Qemu-devel] [Qemu-block] [PATCH COLO-Block v6 07/16] Add new block driver interface to connect/disconnect the remote target
Date: Wed, 1 Jul 2015 09:01:16 +0800	[thread overview]
Message-ID: <55933BDC.40401@cn.fujitsu.com> (raw)
In-Reply-To: <20150630190146.GE2142@work-vm>

On 07/01/2015 03:01 AM, Dr. David Alan Gilbert wrote:
> * Wen Congyang (wency@cn.fujitsu.com) wrote:
>> On 06/27/2015 03:03 AM, Dr. David Alan Gilbert wrote:
> 
> <snip>
> 
>>> Ah, I hadn't realised you could do that; so do you just do:
>>>
>>> migrate_set_parameter colo on
>>> migrate -d -b tcp:otherhhost:port
>>>
>>> How does the secondary know to feed that data straight into the disk without
>>> recording all the old data into the hidden-disk ?
>>
>> hidden disk and active disk will be made empty when starting block replication.
> 
> Hmm, yes - I think I need to update to your current world; in the version
> from the end of May, I get a 'error while loading state for instance 0x0 of device 'block''
> if I try to use migrate -d -b 
> (the bdrv_write fails)

Can you give me both primary and secondary qemu's command? I think the command line is wrong,
and disk migration fails.

> 
>>>> If the user uses mirror job, we don't cancel the mirror job now.
>>>
>>> It would be good to get it to work with mirror, that seems preferred these
>>> days to the old block migration.
>>
>> In normal migration, is mirror job created and cancelled by libvirt?
> 
> Yes, I think so; you should be able to turn on full logging on libvirt and
> watch the qmp commands it sends.

Supporting mirror job in my TODO list now. But I think we should focus the basci function now.

Thanks
Wen Congyang

> 
> Dave
> 
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> .
> 