[sheepdog] [PATCH V2 4/4] collie: introduce '-o, --oid' option to 'collie vdi read' command

[Liu Yuan]

在 2012-8-24 AM12:34，"Yunkai Zhang" <yunkai.me at gmail.com>写道：
>
> On Thu, Aug 23, 2012 at 10:20 PM, MORITA Kazutaka
> <morita.kazutaka at lab.ntt.co.jp> wrote:
> > At Thu, 23 Aug 2012 21:46:55 +0800,
> > Yunkai Zhang wrote:
> >>
> >> When inconsistency happens, in the worst case, we just need to make
> >> replicas with the same value but needn't to care about which replica
> >> is correct.
> >>
> >> But in the best case, only several objects were polluted, then this
> >> patch can give us a chance to verify them, This patch is used to work
> >> with 'collie vdi check' command, that is my original intention when
> >> developed it.
> >
> > Well, replica inconsistency happens only when the VM terminates
> > unexpectedly.  If the vm image needs a fix, the guest os filesystem
> > should fix it.  What sheepdog should do is only keeping consistency so
>
> Can you explain how the guest os files system fix it?
>
> I had discussed with Yuan, he told me that these inconsistent replicas

maybe you misunderstand me. I didn't say it's useless. We can't remove them
at all. I think what Ive said was similar to Kazum

Yuan

> is useless for VM. If so, I will have another question: why not delete
> it directly? Or if these replicas are useful data, How can we randomly
> select a replica?
>
> > that the VMs doesn't read the wrong data as a block storage, isn't it?
> > Have you ever encountered a situation where you need to specify a
> > replica to be recovered?
> >
> > Thanks,
> >
> > Kazutaka
>
>
>
> --
> Yunkai Zhang
> Work at Taobao
> --
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> sheepdog at lists.wpkg.org
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