Return-Path: Delivered-To: apmail-lucene-hadoop-user-archive@locus.apache.org Received: (qmail 49777 invoked from network); 20 Nov 2007 20:47:38 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.2) by minotaur.apache.org with SMTP; 20 Nov 2007 20:47:38 -0000 Received: (qmail 90407 invoked by uid 500); 20 Nov 2007 20:47:18 -0000 Delivered-To: apmail-lucene-hadoop-user-archive@lucene.apache.org Received: (qmail 90371 invoked by uid 500); 20 Nov 2007 20:47:18 -0000 Mailing-List: contact hadoop-user-help@lucene.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: hadoop-user@lucene.apache.org Delivered-To: mailing list hadoop-user@lucene.apache.org Received: (qmail 90362 invoked by uid 99); 20 Nov 2007 20:47:18 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 20 Nov 2007 12:47:18 -0800 X-ASF-Spam-Status: No, hits=4.0 required=10.0 tests=DNS_FROM_OPENWHOIS,FORGED_YAHOO_RCVD,SPF_HELO_PASS,SPF_PASS,WHOIS_MYPRIVREG X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of lists@nabble.com designates 216.139.236.158 as permitted sender) Received: from [216.139.236.158] (HELO kuber.nabble.com) (216.139.236.158) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 20 Nov 2007 20:47:21 +0000 Received: from isper.nabble.com ([192.168.236.156]) by kuber.nabble.com with esmtp (Exim 4.63) (envelope-from ) id 1IuZzo-0004NL-Id for hadoop-user@lucene.apache.org; Tue, 20 Nov 2007 12:47:00 -0800 Message-ID: <13865411.post@talk.nabble.com> Date: Tue, 20 Nov 2007 12:47:00 -0800 (PST) From: j2eeiscool To: hadoop-user@lucene.apache.org Subject: NameNode HA MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Nabble-From: siddiqut@yahoo.com X-Virus-Checked: Checked by ClamAV on apache.org Hi, Based on the documentation I have read, there is one instance of a NameNode. Are there recommended approaches on making the NameNode HA: 1.Have a backup which takes over. Data between primary and backup is shared thru shared files , DB etc. Also does having a single NameNode limit the no. of concurrent HDFS clients ? I understand that HDFS Readers and Writers use the DataNode(s) eventually, but the initial access point is the NameNode. I would really appreciate help on these (I am evaluating HDFS for use as a Concurrent, Reliable, Performant Distributed File System). Thanx, Taj -- View this message in context: http://www.nabble.com/NameNode-HA-tf4846281.html#a13865411 Sent from the Hadoop Users mailing list archive at Nabble.com.