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.
