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From Andrew Purtell <andrew.purt...@gmail.com>
Subject Re: Replication terminology "master-master"
Date Tue, 25 Nov 2014 17:21:20 GMT

> On Nov 25, 2014, at 11:09 AM, Jean-Daniel Cryans <jdcryans@apache.org> wrote:
> 
> "A master can be
> slave too, and a slave a master, and cycles are allowed" since with just
> that you can build everything else.

+1



> On Nov 25, 2014, at 11:09 AM, Jean-Daniel Cryans <jdcryans@apache.org> wrote:
> 
>> On Mon, Nov 24, 2014 at 8:29 PM, lars hofhansl <larsh@apache.org> wrote:
>> 
>> Hmm... From that angle all we really have is master-slave replication,
>> without limit as how it can be setup.A master can be slave too, and a slave
>> a master, and cycles are allowed.
>> I find "cyclical replication" more confusing than "master-master"
>> (although it's true that master-master is strictly a subset of cyclical -
>> just a cycle of two).
> 
> I agree with that.
> 
> 
>> We might want to scrap all the terms and just state (hopefully a bit
>> nicer) what I tried to say in the first two sentences above.
> 
> One thing about "master-master" is that some audiences will get it right
> away, for example folks coming from the MySQL world, but maybe we want to
> skip using it in our doc and just say what you wrote above "A master can be
> slave too, and a slave a master, and cycles are allowed" since with just
> that you can build everything else.
> 
> 
>> -- Lars
>> 
>>      From: Misty Stanley-Jones <mstanleyjones@cloudera.com>
>> To: dev@hbase.apache.org
>> Sent: Monday, November 24, 2014 7:26 PM
>> Subject: Replication terminology "master-master"
>> 
>> Hi all,
>> 
>> I think "master-master" is a term that should be re-thought. It is not
>> really a "type" of replication, but refers to a characteristic of  a
>> cluster, specifically a cluster which participates in multiple clusters
>> with different roles -- it is a slave in one cluster and a master in
>> another cluster. I think with the current terminology, people confuse it
>> with "cyclical" replication, in which two clusters replicate to each other,
>> and eventually each has all the data from both.
>> 
>> Since master-master in this sense is really not a type of replication, I
>> think we should just scrap it. You can have master-slave replication or
>> cyclical replication, or a combination. With master-slave replication, a
>> cluster can fulfill both roles at the same time, as long as it is in
>> different clusters. This is easy to understand as a sort of recursive
>> cascade.
>> 
>> Am I explaining it right, and what do you guys think about changing our
>> terminology?
>> 
>> Thanks,
>> Misty
>> 
>> 
>> 
>> 

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