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From Tamar Fraenkel <ta...@tok-media.com>
Subject Re: running two rings on the same subnet
Date Mon, 05 Mar 2012 11:04:31 GMT
I want tow separate clusters.
*Tamar Fraenkel *
Senior Software Engineer, TOK Media

[image: Inline image 1]

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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