Return-Path: Delivered-To: apmail-hadoop-hbase-user-archive@minotaur.apache.org Received: (qmail 92745 invoked from network); 19 Jun 2009 18:40:51 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.3) by minotaur.apache.org with SMTP; 19 Jun 2009 18:40:51 -0000 Received: (qmail 16409 invoked by uid 500); 19 Jun 2009 18:41:02 -0000 Delivered-To: apmail-hadoop-hbase-user-archive@hadoop.apache.org Received: (qmail 16352 invoked by uid 500); 19 Jun 2009 18:41:02 -0000 Mailing-List: contact hbase-user-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: hbase-user@hadoop.apache.org Delivered-To: mailing list hbase-user@hadoop.apache.org Received: (qmail 16342 invoked by uid 99); 19 Jun 2009 18:41:02 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 19 Jun 2009 18:41:02 +0000 X-ASF-Spam-Status: No, hits=-4.0 required=10.0 tests=RCVD_IN_DNSWL_MED,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: local policy) Received: from [192.100.122.230] (HELO mgw-mx03.nokia.com) (192.100.122.230) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 19 Jun 2009 18:40:52 +0000 Received: from esebh106.NOE.Nokia.com (esebh106.ntc.nokia.com [172.21.138.213]) by mgw-mx03.nokia.com (Switch-3.3.3/Switch-3.3.3) with ESMTP id n5JIeFqJ014441 for ; Fri, 19 Jun 2009 21:40:26 +0300 Received: from vaebh104.NOE.Nokia.com ([10.160.244.30]) by esebh106.NOE.Nokia.com with Microsoft SMTPSVC(6.0.3790.3959); Fri, 19 Jun 2009 21:39:47 +0300 Received: from mgw-da01.ext.nokia.com ([147.243.128.24]) by vaebh104.NOE.Nokia.com over TLS secured channel with Microsoft SMTPSVC(6.0.3790.3959); Fri, 19 Jun 2009 21:39:46 +0300 Received: from [172.19.167.46] (bsdhcp16746.americas.nokia.com [172.19.167.46]) by mgw-da01.ext.nokia.com (Switch-3.2.6/Switch-3.2.6) with ESMTP id n5JIdgHs000928 for ; Fri, 19 Jun 2009 21:39:42 +0300 Subject: Re: State of HA From: Andrew Wharton Reply-To: andrew.wharton@nokia.com To: "hbase-user@hadoop.apache.org" In-Reply-To: <31a243e70906020757n38cbe1a2me83fc7ab1bf9203a@mail.gmail.com> References: <0E94BEEABCAE4C4EAC18B13A7A5C24563A691BDE55@NOK-EUMSG-01.mgdnok.nokia.com> <7c962aed0906011026l2a19a249p78b52abb76e02775@mail.gmail.com> <0E94BEEABCAE4C4EAC18B13A7A5C24563A691BDFE7@NOK-EUMSG-01.mgdnok.nokia.com> <78568af10906011356q7d668068m9263bda5a3e7072a@mail.gmail.com> <0E94BEEABCAE4C4EAC18B13A7A5C24563A692022A3@NOK-EUMSG-01.mgdnok.nokia.com> <31a243e70906020757n38cbe1a2me83fc7ab1bf9203a@mail.gmail.com> Content-Type: text/plain Organization: Nokia, Inc. Date: Fri, 19 Jun 2009 14:39:42 -0400 Message-Id: <1245436782.5132.9.camel@1USL14830.NOE.Nokia.com> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 19 Jun 2009 18:39:46.0944 (UTC) FILETIME=[52011000:01C9F10D] X-Nokia-AV: Clean X-Virus-Checked: Checked by ClamAV on apache.org Does anybody know the state of the Backupnamenode scheme that is referenced here? I am looking for a Jira ticket that might give me some more insight into the timeline for release. The hadoop-general email list doesn't seem to have any information about this issue, which is kind of worrying... TIA. -- Andrew On Tue, 2009-06-02 at 16:57 +0200, ext Jean-Daniel Cryans wrote: > Andrew, > > I think you are confusing some components of the whole stack here. The > Namenode is the master for HDFS just like the HMaster is the master > for HBase. Hadoop is 2 things : HDFS and an implementation of > MapReduce which also has a master, the JobTracker. HBase sits on all > that. > > So with regards with what's fixed, the HMaster SPOF is fixed for 0.20. > The Namenode in 0.20 is still a SPOF. That means, if you want HA, you > should get a really reliable machine for the Namenode but you can put > the HMaster on any nodes you want. > AFAIK, there is a BackupNamenode in Hadoop 0.21 that serves as a > Namenode failover.