From user-return-20597-apmail-cassandra-user-archive=cassandra.apache.org@cassandra.apache.org Thu Sep 8 20:14:33 2011 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 A7B0E7B19 for ; Thu, 8 Sep 2011 20:14:33 +0000 (UTC) Received: (qmail 1284 invoked by uid 500); 8 Sep 2011 20:14:31 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 1179 invoked by uid 500); 8 Sep 2011 20:14:30 -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 1171 invoked by uid 99); 8 Sep 2011 20:14:30 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 08 Sep 2011 20:14:30 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=FREEMAIL_FROM,HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of meatforums@gmail.com designates 209.85.216.172 as permitted sender) Received: from [209.85.216.172] (HELO mail-qy0-f172.google.com) (209.85.216.172) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 08 Sep 2011 20:14:24 +0000 Received: by qyk34 with SMTP id 34so731903qyk.10 for ; Thu, 08 Sep 2011 13:14:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; bh=htWhvXOjdCtY2a1OqYQl4rZMbx5IJFOpTCpF2mzoNLg=; b=qcr+xIHUTXRfypISOAaraOvfxVoLW4oL1MGVqd4sfEVCJ6RkUkf3qrzuDT5xIOinxY nf0h16ZjBhqboi1u8TwRvvJFThgtFLxmY06dLTTcGjg2dL9HQc1uj4sw+TpBmeSDP3TK Q/JmqMCljFIjhbV1w9Ew6YUxInkVzeIg8F7H8= MIME-Version: 1.0 Received: by 10.229.23.212 with SMTP id s20mr901512qcb.86.1315512843788; Thu, 08 Sep 2011 13:14:03 -0700 (PDT) Received: by 10.229.211.84 with HTTP; Thu, 8 Sep 2011 13:14:03 -0700 (PDT) Date: Thu, 8 Sep 2011 13:14:03 -0700 Message-ID: Subject: Question on using consistency level with NetworkTopologyStrategy From: Anand Somani To: user@cassandra.apache.org Content-Type: multipart/alternative; boundary=0016368340d8c0614e04ac73b3c6 X-Virus-Checked: Checked by ClamAV on apache.org --0016368340d8c0614e04ac73b3c6 Content-Type: text/plain; charset=ISO-8859-1 Hi, Have a requirement, where data is spread across multiple DC for disaster recovery. So I would use the NTS, that is clear, but I have some questions with this scenario - I have 2 Data Centers - RF - 2 (active DC) , 2 (passive DC) - with NTS - Consistency level options are - LOCAL_QUORUM and EACH _QUORUM - I want LOCAL_QUORUM and 1 remote copy (not 2) for write to succeed, if I used EACH_QUORUM - it would mean that I need both the remote nodes up (as I understand from http://www.datastax.com/docs/0.8/operations/datacenter ). So if that is my requirement what consistency Level should I be using for my writes? Is that even possible with NTS or another strategy? I could use the SimpleStrategy with Quorum, but that would mean sending 2 copies (instead of 1 per DC that NTS uses to optimize on WAN traffic) to remote DC (since it does not understand DC's)? Thanks Anand --0016368340d8c0614e04ac73b3c6 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi,

Have a requirement, where data is spread across multiple DC for = disaster recovery. So I would use the NTS, that is clear, but I have some q= uestions with this scenario
  • I have 2 Data Centers
  • RF - 2 (active DC) , 2 (passive DC)
  • with NTS - Consistency level op= tions are - LOCAL_QUORUM and EACH _QUORUM
  • I want LOCAL_QUORUM a= nd 1 remote copy (not 2) for write to succeed, if I used EACH_QUORUM - it w= ould mean that I need both the remote nodes up (as I understand from http://www.dat= astax.com/docs/0.8/operations/datacenter).
So if that is my requirement what consistency Level should I be u= sing for my writes? Is that even possible with NTS or another strategy? I c= ould use the SimpleStrategy with Quorum, but that would mean sending 2 copi= es (instead of 1 per DC that NTS uses to optimize on WAN traffic) to remote= DC (since it does not understand DC's)?

Thanks
Anand
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