Tag Archives: R

Apache Hadoop HA Configuration

Categories: General Guest Hadoop HDFS

Disclaimer: Cloudera no longer approves of the recommendations in this post. Please see this documentation for configuration recommendations.

One of the things we get a lot of questions about is how to make Hadoop highly available. There is still a lot of work to be done on this front, but we wanted to take a moment and share the best practices from one of our customers. Check out what Paul George has to say about how they keep thier NameNode up at ContextWeb.

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Job Scheduling in Apache Hadoop

Categories: Hadoop MapReduce

(guest blog post by Matei Zaharia)

When Apache Hadoop started out, it was designed mainly for running large batch jobs such as web indexing and log mining. Users submitted jobs to a queue, and the cluster ran them in order. However, as organizations placed more data in their Hadoop clusters and developed more computations they wanted to run, another use case became attractive: sharing a MapReduce cluster between multiple users.

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Sending Files to Remote Task Nodes with Hadoop MapReduce

Categories: Hadoop MapReduce

It is common for a MapReduce program to require one or more files to be read by each map or reduce task before execution. For example, you may have a lookup table that needs to be parsed before processing a set of records. To address this scenario, Hadoop’s MapReduce implementation includes a distributed file cache that will manage copying your file(s) out to the task execution nodes.

The DistributedCache was introduced in Hadoop 0.7.0;

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