Author Archives: Lars George

NoSQL in a Hadoop World

Categories: Hadoop HBase Impala

The number of powerful data query tools in the Apache Hadoop ecosystem can be confusing, but understanding a few simple things about your needs usually makes the choice easy. 

Ah, the good old days. I recall vividly that in 2007, I was faced to store 1 billion XML documents and make them accessible as well as searchable. I had few choices on a given shoestring budget: build something one my own (it was the rage back then—and still is),

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Getting Started with Big Data Architecture

Categories: Hadoop

What does a “Big Data engineer” do, and what does “Big Data architecture” look like? In this post, you’ll get answers to both questions.

Apache Hadoop has come a long way in its relatively short lifespan. From its beginnings as a reliable storage pool with integrated batch processing using the scalable, parallelizable (though inherently sequential) MapReduce framework, we have witnessed the recent additions of real-time (interactive) components like Impala for interactive SQL queries and integration with Apache Solr as a search engine for free-form text exploration.

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Apache HBase + Apache Hadoop + Xceivers

Categories: Hadoop HBase


Some of the configuration properties found in Apache Hadoop have a direct effect on clients, such as Apache HBase. One of those properties is called “dfs.datanode.max.xcievers”, and belongs to the HDFS subproject. It defines the number of server side threads and – to some extent – sockets used for data connections. Setting this number too low can cause problems as you grow or increase utilization of your cluster. This post will help you to understand what happens between the client and server,

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Hadoop Log Location and Retention

Categories: Hadoop

This post is a follow up to an earlier one called Apache Hadoop Log Files: Where to find them in CDH, and what info they contain. It lists nicely the various places Hadoop uses to store log and other info files while it is running. Over time we have seen changes though in different Hadoop and CDH releases that affect where files are stored or how long they are retained. Below strives to document the status quo (no,

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