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From Prasanth Mathialagan <prasanthmathiala...@gmail.com>
Subject Re: Leader elections between 2 nodes.
Date Thu, 10 May 2018 01:40:34 GMT
For reads, is Quorum necessary? Reads are served from local the local
replica, right?

On Wed, May 9, 2018 at 8:29 AM, Jordan Zimmerman <jordan@jordanzimmerman.com
> wrote:

> A quorum means (n/2)+1 - In a 3 node cluster that is 2. So, if 2 servers
> are up you can achieve quorum.
>
> > we need odd
> > numbers in order to form a quorum
>
> The "odd" in this formula refers to the number of configured servers not
> how many are running at a given time. That's the reasoning for quorum in
> the first place. Quorum I/O ensures that a majority of nodes is referenced
> for reads or writes (in ZooKeeper writes are what matter for quorum).
>
> -Jordan
>
> > On May 9, 2018, at 10:26 AM, Kaushal Shriyan <kaushalshriyan@gmail.com>
> wrote:
> >
> > Hi,
> >
> > In a ensemble of 3 nodes with 1 leader and 2 followers, if the leader
> goes
> > down then two servers can elect a leader among themselves. But we need
> odd
> > numbers in order to form a quorum. I am confused. Please correct me if i
> am
> > understanding it wrong.
> >
> > Any help will be highly appreciable
> >
> > Best Regards,
> >
> > Kaushal
>
>

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