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From Jean-Armel Luce <jaluc...@gmail.com>
Subject Re: Consistency level for system_auth keyspace
Date Thu, 07 Mar 2013 09:06:29 GMT
Hi Vitali,

>From my point of view, I think that what you propose is the right solution.

With READ ONE and WRITE ALL, we shall still have a strong consistency.

I am going to add a comment in the ticket 5310.

Thanks.

Jean Armel


2013/3/7 Vitalii Tymchyshyn <tivv00@gmail.com>

> Why not WRITE.ALL READ.ONE? I don't think permissions are updated often
> and READ.ONE provides maximum availability.
>
>
> 2013/3/4 aaron morton <aaron@thelastpickle.com>
>
>> In this case, it means that if there is a network split between the 2
>> datacenters, it is impossible to get the quorum, and all connections will
>> be rejected.
>>
>> Yes.
>>
>> Is there a reason why Cassandra uses the Quorum consistency level ?
>>
>> I would guess to ensure there is a single, cluster wide, set of
>> permissions.
>>
>> Using LOCAL or one could result in some requests that are rejected being
>> allowed on other nodes.
>>
>> Cheers
>>
>>
>>    -----------------
>> Aaron Morton
>> Freelance Cassandra Developer
>> New Zealand
>>
>> @aaronmorton
>> http://www.thelastpickle.com
>>
>> On 1/03/2013, at 6:40 AM, Jean-Armel Luce <jaluce06@gmail.com> wrote:
>>
>> Hi,
>>
>>
>> I am using Cassandra 1.2.2.
>> There are 16 nodes in my cluster in 2 datacenters (8 nodes in each
>> datacenter).
>> I am using NetworkTopologyStrategy.
>>
>> For information, I set a RF = 6 (3 replicas in each datacenter)
>>
>> With 1.2.2, I am using the new authentication backend
>> PasswordAuthenticator with the authorizer CassandraAuthorizer.
>>
>> In the documentation (
>> http://www.datastax.com/docs/1.2/security/security_keyspace_replication#security-keyspace-replication),
>> it is written that for all system_auth-related queries, Cassandra uses the
>> QUORUM consistency level.
>>
>> In this case, it means that if there is a network split between the 2
>> datacenters, it is impossible to get the quorum, and all connections will
>> be rejected.
>>
>> Is there a reason why Cassandra uses the Quorum consistency level ?
>> Maybe a local_quorum conssitency level (or a one consistency level) could
>> do the job ?
>>
>> Regards
>> Jean Armel
>>
>>
>>
>
>
> --
> Best regards,
>  Vitalii Tymchyshyn
>

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