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From Jean-Armel Luce <jaluc...@gmail.com>
Subject Re: Consistency level for system_auth keyspace
Date Mon, 04 Mar 2013 18:34:37 GMT
Hi Dean,

The new authentication modules currently uses a QUORUM consistency level
when checking the user.
That is the reason why it doesn't work in version 1.2.2.

I thing that using LOCAL_QUORUM or ONE CL instead of QUORUM should solve
this problem. But I didn't see any option in 1.2.2.

Regards.

Jean Armel

2013/3/4 Hiller, Dean <Dean.Hiller@nrel.gov>

> I thought there was already a LOCAL_QUOROM option so things continue to
> work when you get  data center split.
>
> There was also TWO I think as well which allowed 4 nodes(2 in each data
> center) so you can continue to write when data center splits.
>
> Dean
>
> From: Jean-Armel Luce <jaluce06@gmail.com<mailto:jaluce06@gmail.com>>
> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <
> user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
> Date: Monday, March 4, 2013 9:12 AM
> To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <
> user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
> Subject: Re: Consistency level for system_auth keyspace
>
> Hi Aaron,
>
> I have open a ticket in Jira :
> https://issues.apache.org/jira/browse/CASSANDRA-5310
> Reading the user using the QUORUM consistency level means that in case of
> network outage, you are unable to open a connection, and all your data
> become unavailable.
>
> Regards.
>
> Jean Armel
>
> 2013/3/4 aaron morton <aaron@thelastpickle.com<mailto:
> 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<mailto:
> 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
>
>
>

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