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From Eric tamme <eta...@gmail.com>
Subject Re: Docs: Token Selection
Date Thu, 16 Jun 2011 15:36:27 GMT
On Thu, Jun 16, 2011 at 11:11 AM, Sasha Dolgy <sdolgy@gmail.com> wrote:
> So, with ec2 ... 3 regions (DC's), each one is +1 from another....?

I dont use ec2, so I am not familiar with the specifics of deployment
there.  That said, if you have 3 data centers with equal nodes in each
(so that you would calculate the same tokens for each DC) - the first
DC you would add 0, the second DC you would add 1, the third DC you
would add 2.

so it could look like the following

In DC 1
node 1 = 0
node 2 = 85070591730234615865843651857942052864

In DC 2
node 1 = 1
node 2 =  85070591730234615865843651857942052865

In DC 3
node 1 = 2
node 2 =  85070591730234615865843651857942052866

Keep in mind, the only reason you need to offset tokens is if there is
another node that would have the exact same token.  So if you have
different numbers of nodes in different data centers, it is possible
you wont need any token offsets.  Just calculate tokens normally, as
if the DC was the only one, then check for any node in another DC with
the same token and add +1 to offset the token.

-Eric

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