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 3F9A41037C for ; Mon, 3 Jun 2013 20:31:41 +0000 (UTC) Received: (qmail 73898 invoked by uid 500); 3 Jun 2013 20:31:38 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 73871 invoked by uid 500); 3 Jun 2013 20:31:38 -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 73863 invoked by uid 99); 3 Jun 2013 20:31:38 -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 20:31:38 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of comomore@gmail.com designates 209.85.212.46 as permitted sender) Received: from [209.85.212.46] (HELO mail-vb0-f46.google.com) (209.85.212.46) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 03 Jun 2013 20:31:33 +0000 Received: by mail-vb0-f46.google.com with SMTP id 10so1126032vbe.5 for ; Mon, 03 Jun 2013 13:31:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=E6WQYA3f/tTWiyX8mIb8ssW6fDOPfw7db2DoSW8yMOs=; b=TdyrkwpmrnKd7a0khoswmYhqrOHOAi+dMWajWG0YdHEqTRDfF/7PlIibtm+LNEKYif 2E0bKza7ogJG1+q2J/u3SPxzY/4tokHXYkZBB2fa0OSZMLhKAtlQgxotzzGghJMusSbr YiW7hws/YbQCvtzBvAQ3Var2/Nsz8LKpajbqGTfq7wd39iU6FaINWkcvepbN5AEfMq5u eC9x0DibbBryDFCNiCDl7npOvzEpsueIYFLQMR456aFPbvCNRLKzjBSeYfBccGoFCaTv 9F2taYy88q25JlT6vqJyxxge40PS0QDMuir7iCbz1QqUT/UeTnij0nv3j2ROsEY7T+50 vg6w== MIME-Version: 1.0 X-Received: by 10.52.17.203 with SMTP id q11mr14752785vdd.120.1370291472546; Mon, 03 Jun 2013 13:31:12 -0700 (PDT) Received: by 10.220.249.67 with HTTP; Mon, 3 Jun 2013 13:31:12 -0700 (PDT) In-Reply-To: References: Date: Mon, 3 Jun 2013 15:31:12 -0500 Message-ID: Subject: Re: Consistency level for multi-datacenter setup From: srmore To: user@cassandra.apache.org Content-Type: multipart/alternative; boundary=bcaec502d1ec75c37104de45d8c0 X-Virus-Checked: Checked by ClamAV on apache.org --bcaec502d1ec75c37104de45d8c0 Content-Type: text/plain; charset=ISO-8859-1 We observed that as well, please let us know what you find out it would be extremely helpful. There is also this property that you can play with to take care of slow nodes *dynamic_snitch_badness_threshold*. http://www.datastax.com/docs/1.1/configuration/node_configuration#dynamic-snitch-badness-threshold Thanks ! On Mon, Jun 3, 2013 at 3:24 PM, Hiller, Dean wrote: > Also, we had to put a fix into cassandra so it removed "slow nodes" from > the list of nodes to read from. With that fix our QUOROM(not local quorom) > started working again and would easily take the other DC nodes out of the > list of reading from for you as well. I need to circle back to with my > teammate to check if he got his fix posted to the dev list or not. > > Later, > Dean > > From: srmore > > Reply-To: "user@cassandra.apache.org" < > user@cassandra.apache.org> > Date: Monday, June 3, 2013 2:09 PM > To: "user@cassandra.apache.org" < > user@cassandra.apache.org> > Subject: Consistency level for multi-datacenter setup > > I am a bit confused when using the consistency level for multi datacenter > setup. 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 > way) > > I am observing that when I use consistency level 2 for some reason the > coordinate node is picking up the nodes from other datacenter. My > understanding was that Cassandra picks up nodes which are close by (from > local datacenter), 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 > request in order for the request to succeed." > > Does this mean that for multi datacenter we can only use ONE or > LOCAL_QUORUM if we want to use the local datacenter to avoid cross > datacenter latency. > > I am using the GossipingPropertyFileSnitch. > > Thanks ! > > --bcaec502d1ec75c37104de45d8c0 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
We observed that as well, please let us know what you find= out it would be extremely helpful. There is also this property that you ca= n play with=A0 to take care of slow nodes

dynamic_snitch_badness_threshold.

http://www.datastax.com/docs/1.1/con= figuration/node_configuration#dynamic-snitch-badness-threshold

Thanks !



On Mon, Jun 3, 2013 at 3:24 PM, Hiller, Dean <= ;Dean.Hiller@nrel= .gov> wrote:
Also, we had to put a fix into cassandra so = it removed "slow nodes" from the list of nodes to read from. =A0W= ith that fix our QUOROM(not local quorom) started working again and would e= asily take the other DC nodes out of the list of reading from for you as we= ll. =A0I need to circle back to with my teammate to check if he got his fix= posted to the dev list or not.

Later,
Dean

From: srmore <comomore@gmail.com<mailto:comomore@gmail.com&g= t;>
Reply-To: "user@cassandra= .apache.org<mailto:user= @cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
Date: Monday, June 3, 2013 2:09 PM
To: "user@cassandra.apach= e.org<mailto:user@cassa= ndra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
Subject: Consistency level for multi-datacenter setup

I am a bit confused when usin= g the consistency level for multi datacenter setup. Following is my setup:<= br>
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 i= n the same data center as the coordinator node must respond to the client r= equest 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 !


--bcaec502d1ec75c37104de45d8c0--