Return-Path: Delivered-To: apmail-zookeeper-user-archive@www.apache.org Received: (qmail 27413 invoked from network); 9 Dec 2010 20:05:34 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 9 Dec 2010 20:05:34 -0000 Received: (qmail 8029 invoked by uid 500); 9 Dec 2010 20:05:33 -0000 Delivered-To: apmail-zookeeper-user-archive@zookeeper.apache.org Received: (qmail 7999 invoked by uid 500); 9 Dec 2010 20:05:33 -0000 Mailing-List: contact user-help@zookeeper.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@zookeeper.apache.org Delivered-To: mailing list user@zookeeper.apache.org Received: (qmail 7991 invoked by uid 99); 9 Dec 2010 20:05:33 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 09 Dec 2010 20:05:33 +0000 X-ASF-Spam-Status: No, hits=3.3 required=10.0 tests=HTML_MESSAGE,NO_RDNS_DOTCOM_HELO,RCVD_IN_DNSWL_NONE,SPF_NEUTRAL X-Spam-Check-By: apache.org Received-SPF: neutral (nike.apache.org: local policy) Received: from [216.145.54.172] (HELO mrout2.yahoo.com) (216.145.54.172) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 09 Dec 2010 20:05:23 +0000 Received: from SP2-EX07CAS01.ds.corp.yahoo.com (sp2-ex07cas01.corp.sp2.yahoo.com [98.137.59.37]) by mrout2.yahoo.com (8.14.4/8.14.4/y.out) with ESMTP id oB9K4Zbb013814 for ; Thu, 9 Dec 2010 12:04:35 -0800 (PST) Received: from SP2-EX07VS04.ds.corp.yahoo.com ([98.137.59.33]) by SP2-EX07CAS01.ds.corp.yahoo.com ([98.137.59.37]) with mapi; Thu, 9 Dec 2010 12:04:35 -0800 From: Mahadev Konar To: "user@zookeeper.apache.org" Date: Thu, 9 Dec 2010 12:04:34 -0800 Subject: Re: Failure scenarios and consequences Thread-Topic: Failure scenarios and consequences Thread-Index: AcuX2tczy+kYOW60Sb+j6aa+mgx3rAAAXUpX Message-ID: In-Reply-To: Accept-Language: en, en-US Content-Language: en X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en, en-US Content-Type: multipart/alternative; boundary="_000_C926765247DD8mahadevyahooinccom_" MIME-Version: 1.0 X-Virus-Checked: Checked by ClamAV on apache.org --_000_C926765247DD8mahadevyahooinccom_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Jeremy, Responses in line below: On 12/9/10 11:53 AM, "Jeremy Hanna" wrote: I looked around on the wiki and in the user list archives and couldn't find= something definitive about certain failure scenarios. A partition splits the ensemble where a quorum is on one side of the partit= ion -- if the leader is on the quorum side of the partition, what happens to re= ads/writes that go to the non-quorum side? I assume writes return errors b= ecause it can't get to the leader. Reads? > The reads will also fail on all the quorum nodes until a new quorum is el= ected. -- if the leader is on the non-quorum side of the partition, I would assume= that the quorum side of the partition would elect a new leader for those c= lients on its side of the partition. However, is there the possibility for= the leader on the non-quorum side to accept writes before it realizes that= there's no longer a quorum? Just wondering about the possibility of corru= ption and then when the cluster syncs back up how the cluster would handle = that data. > No there isnt. The leader relinquishes its right as a leader as soon as i= t realizes a quorum isnt committing the changes it proposed. (I would be happy to create a wiki page for failure scenarios if one doesn'= t exist that people could add to, but maybe this is just common knowledge.) > Please do! thanks mahadev --_000_C926765247DD8mahadevyahooinccom_--