From user-return-32356-apmail-cassandra-user-archive=cassandra.apache.org@cassandra.apache.org Mon Mar 4 15:45:41 2013 Return-Path: X-Original-To: apmail-cassandra-user-archive@www.apache.org Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 3CA5B918D for ; Mon, 4 Mar 2013 15:45:41 +0000 (UTC) Received: (qmail 89304 invoked by uid 500); 4 Mar 2013 15:45:38 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 89165 invoked by uid 500); 4 Mar 2013 15:45:37 -0000 Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@cassandra.apache.org Delivered-To: mailing list user@cassandra.apache.org Received: (qmail 88860 invoked by uid 99); 4 Mar 2013 15:45:36 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 04 Mar 2013 15:45:36 +0000 X-ASF-Spam-Status: No, hits=2.2 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: local policy) Received: from [208.113.200.5] (HELO homiemail-a44.g.dreamhost.com) (208.113.200.5) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 04 Mar 2013 15:45:30 +0000 Received: from homiemail-a44.g.dreamhost.com (localhost [127.0.0.1]) by homiemail-a44.g.dreamhost.com (Postfix) with ESMTP id 9C79A11806D for ; Mon, 4 Mar 2013 07:45:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=thelastpickle.com; h=from :content-type:message-id:mime-version:subject:date:references:to :in-reply-to; s=thelastpickle.com; bh=QCRK8BSPRIKeUlIWiq0Z5MzUGq Q=; b=U3NJrxXoHPRS4Lrky4RRT1asuojIePElNXbjn8E+psa3DxrUybLKNQufA9 2SbiZDLnMPqA6gEiKOqk9zud8hcJi2Glh0Q3oA6WiFvFZC7B9dokQ18MPajJ+E9F XHq3OXCEV4y7GO86EUs/Pc7EyJbvnKHtw88pSOrofNzbvnKSY= Received: from [192.168.168.119] (c-98-234-52-29.hsd1.ca.comcast.net [98.234.52.29]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) (Authenticated sender: aaron@thelastpickle.com) by homiemail-a44.g.dreamhost.com (Postfix) with ESMTPSA id 79AFD11806C for ; Mon, 4 Mar 2013 07:45:06 -0800 (PST) From: aaron morton Content-Type: multipart/alternative; boundary="Apple-Mail=_BCDB2C0C-530A-4B67-9A6E-94565730CA99" Message-Id: Mime-Version: 1.0 (Mac OS X Mail 6.2 \(1499\)) Subject: Re: Consistency level for system_auth keyspace Date: Mon, 4 Mar 2013 07:45:05 -0800 References: To: user@cassandra.apache.org In-Reply-To: X-Mailer: Apple Mail (2.1499) X-Virus-Checked: Checked by ClamAV on apache.org --Apple-Mail=_BCDB2C0C-530A-4B67-9A6E-94565730CA99 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-1 > 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.=20 > 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.=20 Using LOCAL or one could result in some requests that are rejected being = allowed on other nodes.=20 Cheers ----------------- Aaron Morton Freelance Cassandra Developer New Zealand @aaronmorton http://www.thelastpickle.com On 1/03/2013, at 6:40 AM, Jean-Armel Luce wrote: > Hi, >=20 >=20 > 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. >=20 > For information, I set a RF =3D 6 (3 replicas in each datacenter) >=20 > With 1.2.2, I am using the new authentication backend = PasswordAuthenticator with the authorizer CassandraAuthorizer. >=20 > In the documentation = (http://www.datastax.com/docs/1.2/security/security_keyspace_replication#s= ecurity-keyspace-replication), it is written that for all = system_auth-related queries, Cassandra uses the QUORUM consistency = level. >=20 > 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. >=20 > 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 ? > =20 > Regards > Jean Armel --Apple-Mail=_BCDB2C0C-530A-4B67-9A6E-94565730CA99 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=iso-8859-1 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


=
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 =3D = 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_keysp= ace_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

= --Apple-Mail=_BCDB2C0C-530A-4B67-9A6E-94565730CA99--