How should configuration files of Active and Backup NameNode should differ from each other?
Assume that our Active NameNode died, do we need to anything further DNS record change? We start our Backup NameNode with "-backup" argument. How to convert role to active? From: Dhruba Borthakur Sent: Friday, October 08, 2010 12:49 AM To: hdfs-user@hadoop.apache.org Subject: Re: Backup NameNode ActiveNameNode and BackupNamenode do not automatically exchange roles ever. DataNodes are not informed. One can use Virtual IP failover or DNS to switch so that DataNodes need not know that the Namenode has moved from one machine to another. hope this helps, dhruba On Wed, Oct 6, 2010 at 10:07 PM, Ozcan ILIKHAN <ilik...@cs.wisc.edu> wrote: Hi all, Following questions are specific to v0.21.0. From the user guide it is not clear enough how Active NameNode and Backup Namenode take over role from each other, how DateNode are informed if active NameNode fails (or do they need to be informed?). What is happening in disaster scnerios. While configuring cluster, assume 1 active NameNode, 1 Backup NameNode, 1 Chekpoint NameNode, and the rest of the cluster is assumed to be DataNodes. Which parameters for these 4 types of nodes' hdfs-site.xml and core-site.xml should set, and how should they (config files of 4 type of nodes ) differ from each other. By the way, in order to understand certain functionalities, most of the time we need to go deep into source code. I think it will be good to enrich Hadoop (especially HDFS) documentation. Thanks in advance, Ozcan. -- Connect to me at http://www.facebook.com/dhruba