The link Uma passed already covered that question: http://www.cloudera.com/blog/2009/02/multi-host-secondarynamenode-configuration/ [dfs.http.address in hdfs-site.xml pointing to NN_HOST:50070 should do.]
Also, if you are using the tarball start/stop scripts, putting in the hostname for SNN in the conf/masters list is sufficient to get it auto-started there. On 27-Dec-2011, at 11:36 AM, praveenesh kumar wrote: > Thanks..But, my 1st question is still unanswered. > I have a 8 DN/TT machines and 1 NN machine. > I want to set one of my DN/TT machine as SNN. > How I have to configure my conf/*.xml files to achieve this ? > > Thanks, > Praveenesh > > On Mon, Dec 26, 2011 at 8:44 PM, Harsh J <[email protected]> wrote: >> (Answering beyond Uma's reply) >> >>> Can a DN also act as SNN, any pros and cons of having this configuration ? >> >> You can run SNN on a regular slave box if you can't have a dedicate a box, >> it shouldn't be an issue for small clusters -- Do ensure its disk >> configuration is proper, and its allocated near to the same heap as the >> NameNode is. >> >> For large clusters where the fsimage and periodic edits file sizes are >> larger, it would be worth placing it on a separate box given SNN's >> interactions. >> >> On 26-Dec-2011, at 7:53 PM, Uma Maheswara Rao G wrote: >> >>> Hey Praveenesh, >>> >>> You can start secondary namenode also by just giving the option ./hadoop >>> secondarynamenode >>> >>> DN can not act as seconday namenode. The basic work for seconday namenode >>> is to do checkpointing and getting the edits insync with Namenode till last >>> checkpointing period. DN is to store the real data blocks physically. >>> you need to configure correct namenode http address also for the >>> secondaryNN, so that it can connect NN for checkpointing operations. >>> http://hadoop.apache.org/common/docs/current/hdfs_user_guide.html#Secondary+NameNode >>> You can configure secondary node IP in masters file, start-dfs.sh itself >>> will start the SNN automatically as it starts DN and NN as well. >>> >>> also you can see >>> http://www.cloudera.com/blog/2009/02/multi-host-secondarynamenode-configuration/ >>> >>> Regards, >>> Uma >>> ________________________________________ >>> From: praveenesh kumar [[email protected]] >>> Sent: Monday, December 26, 2011 5:05 PM >>> To: [email protected] >>> Subject: Secondary Namenode on hadoop 0.20.205 ? >>> >>> Hey people, >>> >>> How can we setup another machine in the cluster as Secondary Namenode >>> in hadoop 0.20.205 ? >>> Can a DN also act as SNN, any pros and cons of having this configuration ? >>> >>> Thanks, >>> Praveenesh >>
