Return-Path: X-Original-To: apmail-hbase-dev-archive@www.apache.org Delivered-To: apmail-hbase-dev-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id EAA8310DD9 for ; Tue, 25 Nov 2014 03:28:30 +0000 (UTC) Received: (qmail 94656 invoked by uid 500); 25 Nov 2014 03:28:30 -0000 Delivered-To: apmail-hbase-dev-archive@hbase.apache.org Received: (qmail 94569 invoked by uid 500); 25 Nov 2014 03:28:30 -0000 Mailing-List: contact dev-help@hbase.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@hbase.apache.org Delivered-To: mailing list dev@hbase.apache.org Received: (qmail 94557 invoked by uid 99); 25 Nov 2014 03:28:29 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 25 Nov 2014 03:28:29 +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 (athena.apache.org: domain of mstanleyjones@cloudera.com designates 209.85.212.175 as permitted sender) Received: from [209.85.212.175] (HELO mail-wi0-f175.google.com) (209.85.212.175) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 25 Nov 2014 03:28:24 +0000 Received: by mail-wi0-f175.google.com with SMTP id l15so7762157wiw.8 for ; Mon, 24 Nov 2014 19:27:18 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:from:date:message-id:subject:to :content-type; bh=/IykUUxTnKApSgiuo0FWj8qr1vCdcpVTNuwiOW75VDk=; b=hGEkx8gltu5aC9DpB0pvdrSN+yciCv6v6OW8fj+Ery6deECVhacfzPErlq3M1FBcc7 f8MdZbTuwajh27lmGTy50dZfU7svZtm44Rt83ENpWPycPSPdJDqiVLnI5xeq9eC3TIM0 KVcaZt3byHcKrhd714AqOR7rEEx+qUCBgNfNKy8CDdeXTnC7QAHJWOau8PoKssMLz8mX JQ4aIAUpnO41UHDgwIwdrejxAg9OT2MxX5GpN/l5ndj0d9d5BALuU6apTXRcX6ndTezq jDdCUjGpmVKkbXHB0vBdVij8Cp2IS4MHdcWrRQOoQ98vTVbv/Al9njWj+Sg1Hq9q2boF 9jWg== X-Gm-Message-State: ALoCoQlusqCH4CqBMl8hou6Y5t4kEFPnEFqQxUC8vloKxHMt9SiGNQ8XSw7hOG3v2DwPgRi8l+8I X-Received: by 10.194.121.167 with SMTP id ll7mr33219294wjb.26.1416886038515; Mon, 24 Nov 2014 19:27:18 -0800 (PST) MIME-Version: 1.0 Received: by 10.27.14.8 with HTTP; Mon, 24 Nov 2014 19:26:58 -0800 (PST) From: Misty Stanley-Jones Date: Tue, 25 Nov 2014 13:26:58 +1000 Message-ID: Subject: Replication terminology "master-master" To: dev@hbase.apache.org Content-Type: multipart/alternative; boundary=089e011760190366c60508a67de4 X-Virus-Checked: Checked by ClamAV on apache.org --089e011760190366c60508a67de4 Content-Type: text/plain; charset=UTF-8 Hi all, I think "master-master" is a term that should be re-thought. It is not really a "type" of replication, but refers to a characteristic of a cluster, specifically a cluster which participates in multiple clusters with different roles -- it is a slave in one cluster and a master in another cluster. I think with the current terminology, people confuse it with "cyclical" replication, in which two clusters replicate to each other, and eventually each has all the data from both. Since master-master in this sense is really not a type of replication, I think we should just scrap it. You can have master-slave replication or cyclical replication, or a combination. With master-slave replication, a cluster can fulfill both roles at the same time, as long as it is in different clusters. This is easy to understand as a sort of recursive cascade. Am I explaining it right, and what do you guys think about changing our terminology? Thanks, Misty --089e011760190366c60508a67de4--