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 2349310307 for ; Mon, 3 Jun 2013 20:22:01 +0000 (UTC) Received: (qmail 38490 invoked by uid 500); 3 Jun 2013 20:21:58 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 38464 invoked by uid 500); 3 Jun 2013 20:21:58 -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 38456 invoked by uid 99); 3 Jun 2013 20:21:58 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 03 Jun 2013 20:21:58 +0000 X-ASF-Spam-Status: No, hits=-2.3 required=5.0 tests=RCVD_IN_DNSWL_MED,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: local policy) Received: from [192.174.58.134] (HELO XEDGEA.nrel.gov) (192.174.58.134) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 03 Jun 2013 20:21:52 +0000 Received: from XHUBA.nrel.gov (10.20.4.58) by XEDGEA.nrel.gov (192.174.58.134) with Microsoft SMTP Server (TLS) id 8.3.298.1; Mon, 3 Jun 2013 14:21:20 -0600 Received: from MAILBOX2.nrel.gov ([fe80::48b0:b121:8465:5e5]) by XHUBA.nrel.gov ([::1]) with mapi; Mon, 3 Jun 2013 14:21:29 -0600 From: "Hiller, Dean" To: "user@cassandra.apache.org" Date: Mon, 3 Jun 2013 14:21:25 -0600 Subject: Re: Consistency level for multi-datacenter setup Thread-Topic: Consistency level for multi-datacenter setup Thread-Index: Ac5gl+3GqXjpC3LfRMGl7NeDzPoiMQ== Message-ID: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Microsoft-MacOutlook/14.3.4.130416 acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Virus-Checked: Checked by ClamAV on apache.org What happens when you use CL=3DTWO. Dean From: srmore > Reply-To: "user@cassandra.apache.org" > Date: Monday, June 3, 2013 2:09 PM To: "user@cassandra.apache.org" > Subject: Consistency level for multi-datacenter setup I am a bit confused when using the consistency level for multi datacenter s= etup. Following is my setup: I have 4 nodes the way these are set up are Node 1 DC 1 - N1DC1 Node 2 DC 1 - N2DC1 Node 1 DC 2 - N1DC2 Node 2 DC 2 - N2DC2 I setup a delay in between two datacenters (DC1 and DC2 around 1 sec one wa= y) I am observing that when I use consistency level 2 for some reason the coor= dinate node is picking up the nodes from other datacenter. My understanding= was that Cassandra picks up nodes which are close by (from local datacente= r), determined by Gossip but looks like that's not the case. I found the following comment on Datastax website : "If using a consistency level of ONE or LOCAL_QUORUM, only the nodes in the= same data center as the coordinator node must respond to the client reques= t in order for the request to succeed." Does this mean that for multi datacenter we can only use ONE or LOCAL_QUORU= M if we want to use the local datacenter to avoid cross datacenter latency. I am using the GossipingPropertyFileSnitch. Thanks !