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From Flavio P JUNQUEIRA <...@apache.org>
Subject Re: Zab Failure scenario
Date Sun, 27 Sep 2015 16:21:08 GMT
In 3, it is not exactly a pending proposal, but if the leader has 10 in its
log, then it will make sure 10 is committed by the end of the
synchronisation phase and before it becomes established.

I'm not sure why you are assuming 3.4.6,  though. Why is it relevant for
this question?

-Flavio
On 27 Sep 2015 4:51 pm, "Ibrahim El-sanosi (PGR)" <
i.s.el-sanosi@newcastle.ac.uk> wrote:

> Assume we use ZooKeeper 3.4.6 and we have 3-server cluster. Leader (L),
> follower1 (F1) and follower2 (F2). The scenario is as following:
>
> 1.       Leader sends a proposal with Zxid = 10.
>
> 2.       F2 crashes before receiving P10. F1 logs, sends an ACK and
> crashes.
> As there is no quorum  supporting L, L moves to LOOKING phase to find a
> quorum and elects new leader. After sometime F1 wakes up and form a quorum
> with L.  Both F1 and L (pervious leader) have same state (zxid =10 in their
> log). Therefore the process which has the large myid will be a leader,
> assume L (pervious leader) has larger myid, So,
>
> 3.       L sends a pending proposal with Zxid =10 to F1.
>
> 4.       F1 logs and sends an ACK.
>
> 5.       Upon receiving ACK, L commits p10 and sends an ACK.
>
>
>
> (1)    Is this true or false?
>
> (2)    Regards,
> Ibrahim
>
>

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