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From Ulul <had...@ulul.org>
Subject Re: adding another namenode to an existing hadoop instance
Date Wed, 18 Feb 2015 20:14:19 GMT
Hi

This is not your hadoop version but your java version you displayed
For hadoop version remove the dash : hdfs version

The dfs.namenode.name.dir is the dir for the namenode process to store 
the filesystem image. It is unique.

What you seem to be looking for is Namenode HA, how to install a standby 
NN (and not a secondary NN which is the poorly named process that merges 
FS changes into the fs image).
This exists in Hadoop v2.x

You can find doc there : 
https://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-hdfs/HDFSHighAvailabilityWithQJM.html
Since you seem to already have a running cluster here is a blog post 
about configuring HA on an existing cluster (I didn't try it) : 
http://johnjianfang.blogspot.fr/2014/09/how-to-configure-hadoop-ha-for-running.html

But you need to test thoroughly on a test environment before doing 
anything on a cluster holding production data

Cheers
Ulul

Le 18/02/2015 10:50, Mich Talebzadeh a écrit :
>
> Hi,
>
> I have a Hadoop instance (single node) installed on RHES5 running OK.
>
> The version of Hadoop is
>
> hdfs -version
>
> java version "1.7.0_25"
>
> Java(TM) SE Runtime Environment (build 1.7.0_25-b15)
>
> Java HotSpot(TM) 64-Bit Server VM (build 23.25-b01, mixed mode)
>
> I would like to add another file to namenode in hdfs-site.xml. That is 
> effectively building resiliency and multi-plexing it.
>
> The new file will be on Solid State Disk. I tried adding it to 
> hdfs-site.xml file by having
>
> <property>
>
> <name>dfs.namenode.name.dir</name>
>
> <value>file:/work/hadoop/hadoop_store/hdfs/namenode</value>
>
> </property>
>
> And changing it to
>
> <property>
>
> <name>dfs.namenode.name.dir</name>
>
> <value>file:/work/hadoop/hadoop_store/hdfs/namenode</value>
>
> *<value>file:/ssddata6/hadoop/hadoop_store/hdfs/namenode</value>*
>
> </property>
>
> But it does not work!
>
> Any ideas if one can add the secondary namenode file without losing 
> data etc?
>
> Thanks
>
> Mich Talebzadeh
>
> http://talebzadehmich.wordpress.com
>
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