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Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's descrip
From: |
Wen Congyang |
Subject: |
Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description |
Date: |
Thu, 23 Apr 2015 19:35:49 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 |
On 04/23/2015 06:44 PM, Paolo Bonzini wrote:
>
>
> On 23/04/2015 12:40, Kevin Wolf wrote:
>> The question that is still open for me is whether it would be a colo.c
>> or an active-mirror.c, i.e. if this would be tied specifically to COLO
>> or if it could be kept generic enough that it could be used for other
>> use cases as well.
>
> Understood (now).
>
>>>> What I think is really needed here is essentially an active mirror
>>>> filter.
>>>
>>> Yes, an active synchronous mirror. It can be either a filter or a
>>> device. Has anyone ever come up with a design for filters? Colo
>>> doesn't need much more complexity than a "toy" blkverify filter.
>>
>> I think what we're doing now for quorum/blkverify/blkdebug is okay.
>>
>> The tricky and yet unsolved part is how to add/remove filter BDSes at
>> runtime (dynamic reconfiguration), but IIUC that isn't needed here.
>
> Yes, it is. The "defer connection to NBD when replication is started"
> is effectively "add the COLO filter" (with the NBD connection as a
> children) when replication is started.
>
> Similarly "close the NBD device when replication is stopped" is
> effectively "remove the COLO filter" (which brings the NBD connection
> down with it).
Hmm, I don't understand it clearly. Do you mean:
1. COLO filter is quorum's child
2. We can add/remove quorum's child at run-time.
If I misunderstand something, please correct me.
Thanks
Wen Congyang
>
> Paolo
> .
>
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, (continued)
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Wen Congyang, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Paolo Bonzini, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Kevin Wolf, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Paolo Bonzini, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Kevin Wolf, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Paolo Bonzini, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description,
Wen Congyang <=
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Kevin Wolf, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Paolo Bonzini, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Dr. David Alan Gilbert, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Paolo Bonzini, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Dr. David Alan Gilbert, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Paolo Bonzini, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Fam Zheng, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Wen Congyang, 2015/04/23
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Paolo Bonzini, 2015/04/24
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Wen Congyang, 2015/04/24