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Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's descrip
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description |
Date: |
Thu, 23 Apr 2015 13:19:53 +0100 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
* Paolo Bonzini (address@hidden) wrote:
>
>
> On 23/04/2015 14:05, Dr. David Alan Gilbert wrote:
> > As presented at the moment, I don't see there's any dynamic reconfiguration
> > on the primary side at the moment
>
> 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
Dave
>
> Paolo
>
> - it starts up in the configuration with
> > the quorum(disk, NBD), and that's the way it stays throughout the
> > fault-tolerant
> > setup; the primary doesn't start running until the secondary is connected.
> >
> > Similarly the secondary startups in the configuration and stays that way;
> > the interesting question to me is what happens after a failure.
> >
> > If the secondary fails, then your primary is still quorum(disk, NBD) but
> > the NBD side is dead - so I don't think you need to do anything there
> > immediately.
> >
> > If the primary fails, and the secondary takes over, then a lot of the
> > stuff on the secondary now becomes redundent; does that stay the same
> > and just operate in some form of passthrough - or does it need to
> > change configuration?
> >
> > The hard part to me is how to bring it back into fault-tolerance now;
> > after a primary failure, the secondary now needs to morph into something
> > like a primary, and somehow you need to bring up a new secondary
> > and get that new secondary an image of the primaries current disk.
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- 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, 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, 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, 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 <=
- 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
- Re: [Qemu-block] [PATCH COLO v3 01/14] docs: block replication's description, Dr. David Alan Gilbert, 2015/04/24
- 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
- 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