Hadoop defintive guide says - Each Namenode runs a lightweight failover controller process whose job it is to monitor its Namenode for failures (using a simple heartbeat mechanism) and ...

I find that my Impala swarm performs not stable, normally it takes only a few seconds (less than 10s) to finish a query, but occasionally it will take more than 40s (and this situation will last fo...

We have two HDP cluster's setup let's call them A and B. CLUSTER A NODES : It contains a total of 20 commodity machines. There are 20 data nodes. As namenode HA is configured, there is one act...

I have been trying to install Hadoop on Windows 7 for quite sometime now. I am following this blog for instructions. But unfortunately I have not been be able to run the Namenode. There seems to b...

I have a namenode that had to be brought down for an emergency that has not had an FSImage taken for 9 months and has about 5TB worth of edit files to process in its next restart. The secondary nam...

When i try to start the hadoop on master node i am getting the following output.and the namenode is not starting. [hduser@dellnode1 ~]$ start-dfs.sh starting namenode, logging to /usr/local/hadoop...

I have updated the /conf/slaves file on the Hadoop master node with the hostnames of my slave nodes, but I'm not able to start the slaves from the master. I have to individually start the slaves, a...

we have a old hadoop cluster machine hadoop - version 2.6 all machines in the cluster are redhat version - 7.3 we have a problem to start the standby name-node on the last master machine from...

Any one know how many bytes occupy per file in namenode of Hdfs? I want to estimate how many files can store in single namenode of 32G memory.

I know both these properties are related to namenode. But what is the actual difference between them?