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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Replica data distributing between racks
Date Tue, 03 May 2011 14:13:36 GMT
Right, when you are computing balanced RP tokens for NTS you need to
compute the tokens for each DC independently.

On Tue, May 3, 2011 at 6:23 AM, aaron morton <aaron@thelastpickle.com> wrote:
> I've been digging into this and worked was able to reproduce something, not sure if it's
a fault and I can't work on it any more tonight.
>
>
> To reproduce:
> - 2 node cluster on my mac book
> - set the tokens as if they were nodes 3 and 4 in a 4 node cluster, e.g. node 1 with
85070591730234615865843651857942052864 and node 2 127605887595351923798765477786913079296
> - set cassandra-topology.properties to put the nodes in DC1 on RAC1 and RAC2
> - create a keyspace using NTS and strategy_options = [{DC1:1}]
>
> Inserted 10 rows they were distributed as
> - node 1 - 9 rows
> - node 2 - 1 row
>
> I *think* the problem has to do with TokenMetadata.firstTokenIndex(). It often says the
closest token to a key is the node 1 because in effect...
>
> - node 1 is responsible for 0 to 85070591730234615865843651857942052864
> - node 2 is responsible for 85070591730234615865843651857942052864 to 127605887595351923798765477786913079296
> - AND node 1 does the wrap around from 127605887595351923798765477786913079296 to 0 as
keys that would insert past the last token in the ring array wrap to 0 because  insertMin
is false.
>
> Thoughts ?
>
> Aaron
>
>
> On 3 May 2011, at 10:29, Eric tamme wrote:
>
>> On Mon, May 2, 2011 at 5:59 PM, aaron morton <aaron@thelastpickle.com> wrote:
>>> My bad, I missed the way TokenMetadata.ringIterator() and firstTokenIndex() work.
>>>
>>> Eric, can you show the output from nodetool ring ?
>>>
>>>
>>
>> Sorry if the previous paste was way to unformatted, here is a
>> pastie.org link with nicer formatting of nodetool ring output than
>> plain text email allows.
>>
>> http://pastie.org/private/50khpakpffjhsmgf66oetg
>
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com

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