[sheepdog] [PATCH 0/2] add cache options 'page' and 'unsafe'
morita.kazutaka at lab.ntt.co.jp
Mon Oct 22 08:50:32 CEST 2012
At Mon, 22 Oct 2012 14:36:39 +0800,
Liu Yuan wrote:
> On 10/22/2012 02:26 PM, MORITA Kazutaka wrote:
> >> > If disk is failed, I don't think buffered read/write will succeed
> >> > because we will fail to open the fd. So your rationale about unsafe
> >> > seems useless: no one will actually use it.
> > Actually we NTT would use it. We have data centers which can supply
> > reliable power and we can regard that, if data is replicated to
> > multiple memories, the data is safe. If disk is failed with 'unsafe'
> > mode, the node will be completely replaced with a new machine and
> > there is no risk of reading invalid data.
> So this kind of machine is smart and fail-over is taken behind the
> scene, sounds interesting.
> If there is actual users, I am not against adding it. But 'unsafe' looks
> a little bit vague, call it as backend:nosync looks more straight
> forward to what it really means.
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