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From sankalp kohli <kohlisank...@gmail.com>
Subject Re: How to avoid inter-dc read requests
Date Sun, 21 Jul 2013 20:40:14 GMT
There can be multiple reasons for that
1) Background read repairs.
2) Your data is not consistent and leading to read repairs.
3) For writes, irrespective of the consistency used, a single write request
will goto other DC
4) You might be running other nodetools commands like repair.
read_repair_chanceĀ¶<http://www.datastax.com/docs/1.2/configuration/storage_configuration#read-repair-chance>

(Default: 0.1 or 1) Specifies the probability with which read repairs
should be invoked on non-quorum reads. The value must be between 0 and 1.
For tables created in versions of Cassandra before 1.0, it defaults to 1.
For tables created in versions of Cassandra 1.0 and higher, it defaults to
0.1. However, for Cassandra 1.0, the default is 1.0 if you use CLI or any
Thrift client, such as Hector or pycassa, and is 0.1 if you use CQL.


On Sun, Jul 21, 2013 at 10:26 AM, Omar Shibli <omar@eyeviewdigital.com>wrote:

> One more thing, I'm doing a lot of key slice read requests, is that
> supposed to change anything?
>
>
> On Sun, Jul 21, 2013 at 8:21 PM, Omar Shibli <omar@eyeviewdigital.com>wrote:
>
>> I'm seeing a lot of inter-dc read requests, although I've followed
>> DataStax guidelines for multi-dc deployment
>> http://www.datastax.com/dev/blog/deploying-cassandra-across-multiple-data-centers
>>
>> Here is my setup:
>> 2 data centers within the same region (AWS)
>> Targeting DC, RP 3, 6 nodes
>> Analytic DC, RP 3, 11 nodes
>>
>> All the read/write request are issued with CL local quorum, but still
>> there're a lot of inter-dc read request.
>> Any suggestion, or am I missing something?
>>
>> Thanks in advance,
>>
>
>

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