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From: Le Cyberian <lecyberian@gmail.com>
Date: Mon, 6 Mar 2017 23:42:06 +0100
Message-ID: <CAM3razj_obbw0xej_iry7Q5Ay+LcMNB1SrfvYhXtDXCYviiFsw@mail.gmail.com>
Subject: Re: Zookeeper Cross Datacenter Cluster
To: "Van Klaveren, Brian N." <bvan@slac.stanford.edu>
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archived-at: Mon, 06 Mar 2017 22:42:19 -0000

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Thank for your replies.

I see, in that way then failover won't be possible as if the main/major DC
is down.

Is there something i can do using hierarchical quorum groups or observers ?

I am quiet confused to achieve this setup somehow, as how someone would
build a failover over 2 dc's :-/

On Mon, Mar 6, 2017 at 11:08 PM, Van Klaveren, Brian N. <
bvan@slac.stanford.edu> wrote:

> Or, an extra server in a third datacenter to break the tie.
>
> Brian
>
>
> > On Mar 6, 2017, at 2:05 PM, Jordan Zimmerman <jordan@jordanzimmerman.com>
> wrote:
> >
> > This scenario is not possible. An even number of servers doesn't help
> you as a quorum in ZooKeeper is (N/2)+1. So, if you put 2 servers in each
> DC, a network partition would disable BOTH DCs. (4/2)+1 == 3. So, the only
> option is to choose one of the DCs as the main DC and put an extra server
> there. This way you could lose the "minor" DC.
> >
> > -Jordan
> >
> >> On Mar 6, 2017, at 11:34 AM, Le Cyberian <lecyberian@gmail.com> wrote:
> >>
> >> Hi Guys,
> >>
> >> I would like to have Kafka Cluster which is dependent on Zookeeper like
> >> many other great projects out their. Kafka would have 4 nodes as its
> >> cluster since their having even number is not a problem because it does
> >> leader election based its config it keeps in zookeeper.
> >>
> >> My scenario is having two server rooms on different floors having fiber
> >> connectivity with each other so network latency / lag is almost like a
> >> local connection.
> >>
> >> However, I would like to implement zookeeper cluster between both of
> them
> >> for auto-failover / redundancy purposes. So if one server room is down
> >> other should work properly.
> >>
> >> For example: on a 5 node zookeeper cluster distributed on both of the
> >> server rooms with 3 in one and 2 in other would give me 2 node failure
> >> tolerance, However if the server room which has 3 servers is down then
> >> ensemble would be broken and split brain.
> >>
> >> Can you please suggest how to achieve this to have failover / redundancy
> >> between two server rooms or two locations lets say ?
> >>
> >> Is it possible to run 3 node cluster in each server room and have some
> sort
> >> of master-master between them ?
> >>
> >> Thank for your time and helping out in advance.
> >>
> >> Kind regards,
> >>
> >> Le
> >
>
>

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