Return-Path: Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: (qmail 95919 invoked from network); 12 Dec 2010 17:50:25 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 12 Dec 2010 17:50:25 -0000 Received: (qmail 85978 invoked by uid 500); 12 Dec 2010 17:50:23 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 85795 invoked by uid 500); 12 Dec 2010 17:50:21 -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 85787 invoked by uid 99); 12 Dec 2010 17:50:20 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 12 Dec 2010 17:50:20 +0000 X-ASF-Spam-Status: No, hits=-0.0 required=10.0 tests=RCVD_IN_DNSWL_LOW,SPF_NEUTRAL X-Spam-Check-By: apache.org Received-SPF: neutral (athena.apache.org: local policy) Received: from [209.85.161.171] (HELO mail-gx0-f171.google.com) (209.85.161.171) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 12 Dec 2010 17:50:11 +0000 Received: by gxk8 with SMTP id 8so4180134gxk.30 for ; Sun, 12 Dec 2010 09:49:49 -0800 (PST) MIME-Version: 1.0 Received: by 10.150.96.9 with SMTP id t9mr4037384ybb.318.1292176188893; Sun, 12 Dec 2010 09:49:48 -0800 (PST) Sender: scode@scode.org Received: by 10.150.220.9 with HTTP; Sun, 12 Dec 2010 09:49:48 -0800 (PST) X-Originating-IP: [213.114.157.242] In-Reply-To: References: Date: Sun, 12 Dec 2010 18:49:48 +0100 X-Google-Sender-Auth: 6Fb2FHzZp14RL3BD98b8m2chs88 Message-ID: Subject: Re: Quorum and Datacenter loss From: Peter Schuller To: user@cassandra.apache.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable > Thanks a lot Peter. =C2=A0 So basically we would need to choose a > consistency other than QUORUM. =C2=A0 =C2=A0I think in our case consisten= cy is > not necessarily an issue since our data is write-once, read-many > (immutable data). =C2=A0 I suppose having a replication factor of 4 would > result in two nodes in each datacenter having a copy of the data. =C2=A0 = If > there's a flaw in my logic, please let me know : ] It would, but note that if you're writing at consistency level ONE only a single copy of the data is required to exist before your write is ACK:ed back to the client (but it will still be replicated). --=20 / Peter Schuller