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From aaron morton <aa...@thelastpickle.com>
Subject Re: running two rings on the same subnet
Date Mon, 05 Mar 2012 17:30:50 GMT
Create nodes that do not share seeds, and give the clusters different names as a safety measure.


Cheers

-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 6/03/2012, at 12:04 AM, Tamar Fraenkel wrote:

> I want tow separate clusters.
> Tamar Fraenkel 
> Senior Software Engineer, TOK Media 
> 
> <tokLogo.png>
> 
> tamar@tok-media.com
> Tel:   +972 2 6409736 
> Mob:  +972 54 8356490 
> Fax:   +972 2 5612956 
> 
> 
> 
> 
> 
> On Mon, Mar 5, 2012 at 12:48 PM, aaron morton <aaron@thelastpickle.com> wrote:
> Do you want to create two separate clusters or a single cluster with two data centres
? 
> 
> If it's the later, token selection is discussed here http://www.datastax.com/docs/1.0/install/cluster_init#token-gen-cassandra
>  
>> Moreover all tokens must be unique (even across datacenters), although - from pure
curiosity - I wonder what is the rationale behind this.
> Otherwise data is not evenly distributed.
> 
>> By the way, can someone enlighten me about the first line in the output of the nodetool.
Obviously it contains a token, but nothing else. It seems like a formatting glitch, but maybe
it has a role. 
> It's the exclusive lower bound token for the first node in the ring. This also happens
to be the token for the last node in the ring. 
> 
> In your setup 
> 10.0.0.19 "owns" (85070591730234615865843651857942052864+1) to 0
> 10.0.0.28 "owns"  (0 + 1) to 85070591730234615865843651857942052864
> 
> (does not imply primary replica, just used to map keys to nodes.)
>  
> 
> 
> -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
> 
> On 5/03/2012, at 11:38 PM, Hontvári József Levente wrote:
> 
>> You have to use PropertyFileSnitch and NetworkTopologyStrategy to create a multi-datacenter
setup with two circles. You can start reading from this page:
>> http://www.datastax.com/docs/1.0/cluster_architecture/replication#about-replica-placement-strategy
>> 
>> Moreover all tokens must be unique (even across datacenters), although - from pure
curiosity - I wonder what is the rationale behind this.
>> 
>> By the way, can someone enlighten me about the first line in the output of the nodetool.
Obviously it contains a token, but nothing else. It seems like a formatting glitch, but maybe
it has a role. 
>> 
>> On 2012.03.05. 11:06, Tamar Fraenkel wrote:
>>> Hi!
>>> I have a Cassandra  cluster with two nodes
>>> 
>>> nodetool ring -h localhost
>>> Address         DC          Rack        Status State   Load            Owns 
  Token
>>>                                                                             
  85070591730234615865843651857942052864
>>> 10.0.0.19       datacenter1 rack1       Up     Normal  488.74 KB       50.00%
 0
>>> 10.0.0.28       datacenter1 rack1       Up     Normal  504.63 KB       50.00%
 85070591730234615865843651857942052864
>>> 
>>> I want to create a second ring with the same name but two different nodes.
>>> using tokengentool I get the same tokens as they are affected from the number
of nodes in a ring.
>>> 
>>> My question is like this:
>>> Lets say I create two new VMs, with IPs: 10.0.0.31 and 10.0.0.11
>>> In 10.0.0.31 cassandra.yaml I will set
>>> initial_token: 0
>>> seeds: "10.0.0.31"
>>> listen_address: 10.0.0.31
>>> rpc_address: 0.0.0.0
>>> 
>>> In 10.0.0.11 cassandra.yaml I will set
>>> initial_token: 85070591730234615865843651857942052864
>>> seeds: "10.0.0.31"
>>> listen_address: 10.0.0.11
>>> rpc_address: 0.0.0.0 
>>> 
>>> Would the rings be separate?
>>> 
>>> Thanks,
>>> 
>>> Tamar Fraenkel 
>>> Senior Software Engineer, TOK Media 
>>> 
>>> <Mail Attachment.png>
>>> 
>>> 
>>> tamar@tok-media.com
>>> Tel:   +972 2 6409736 
>>> Mob:  +972 54 8356490 
>>> Fax:   +972 2 5612956 
>>> 
>>> 
>>> 
>> 
> 
> 


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