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From "" <>
Subject Re: Cannot achieve consistency level LOCAL_ONE
Date Wed, 14 Jun 2017 09:16:24 GMT
Thanks for the detail explanation. You did solve my problem.

From: Oleksandr Shulgin
Date: 2017-06-14 17:09
CC: user
Subject: Re: Cannot achieve consistency level LOCAL_ONE
On Wed, Jun 14, 2017 at 10:46 AM, <> wrote:
Thanks for the reply.
My system_auth settings is as below and what should I do with it? And I'm interested why the
newly added node is responsible for the user authentication?

CREATE KEYSPACE system_auth WITH replication = {'class': 'SimpleStrategy', 'replication_factor':
'1'}  AND durable_writes = true;

You should change the replication options to use NetworkTopologyStrategy and a replication
factor greater than 1 in each DC.  It is not uncommon to set it to the number of nodes in
the DC, and is actually recommended by the following piece of documentation:

For version 3, the official doc says to set it to 3-5 nodes per DC:

In general there is no drawback when setting the RF for system_auth to the number of nodes
in DC, unless you're relying on the default superuser named "cassandra" being able to login
at all times.  This user is special and it requires LOCAL_QUORUM in order to log in, while
any other user (including non-default superusers) require only LOCAL_ONE.

As to the reason why the new node is responsible for authenticating your application user.
 There is no particular reason for that.  The new node is assigned a random set of tokens
and it happened to be responsible for that user, while some of the old nodes is no longer
responsible (remember, you have RF=1).

Hope this helps,

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