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From Jeff Genender <>
Subject Re: gcache implementation ideas[long]
Date Thu, 14 Sep 2006 14:50:32 GMT
Hi Gianny,

Thanks for the comments.  I am not so sure I want to inject election or
quorum into the mix as I want the first pass to be as simple as
possible.  For the sake of simplicity, already knowing the order will

As I thought about this more, if a slave comes back, it can notify the
other slaves that its alive and then it's back in its proper order.
Keep in mind, an intermediate slave only really needs to notify the
master and other slaves that it's back.


Gianny Damour wrote:
> On 14/09/2006, at 10:58 PM, Jacek Laskowski wrote:
>> On 9/14/06, Jeff Genender <> wrote:
>>> David Jencks wrote:
>>> > - slave 1 (or any intermediate slave) goes down.
>>> > - slave 1 (or any intermediate slave) comes back up
>>> > - slave n (last slave) goes down.
>>> All great questions.  I would like feedback here.
>> See above. The next slave will act as a master until all are gone and
>> the cluster is deemed to have failed. The way 'the next' is computed
>> depends on the magical strategy that's in use (it could be the next in
>> the sense of a list concept or computed randomly).
> I agree. I think that the way this could be achieved is by the mean of
> an  ActiveCluster or WADI like API. Basically, each node executes
> locally an election strategy, when a failure is detected. If the
> election strategy implementation has a determistic outcome, i.e. each
> node uses the same list of nodes and each of them elects the same one,
> then you have your next master. For instance, the WADI implementation is
> to use the oldest node of the cluster.
> I think that if each node picks a node at random, then each one will
> have to broadcast their selection to the other nodes. I believe that if
> one of them has quorum, then each node does know now which of them is
> master.
> Thanks,
> Gianny
>> Jacek
>> --Jacek Laskowski

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