The Apache Hadoop software library is a framework that allows for the distributed processing of large data sets across clusters of computers using simple programming models.

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How to use MRUnit [migrated]

I know that we can use MRUnit to test our mapreduce program, so I downloaded two files: "apache-mrunit-1.1.0-hadoop2-bin.tar.gz" and "apache-mrunit-1.1.0-hadoop2-src.tar.gz", but I don't know what to ...
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Is hadoop designed only for “simple” data processing jobs, where communications between the distributed nodes are sparse?

I am not a professional coder, but rather an engineer/mathematician that uses computer to solve numerical problems. So far most of my problems are math-related, such as solving large scale linear ...
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1answer
510 views

Hadoop and Object Reuse, Why?

In Hadoop, objects passed to reducers are reused. This is extremely surprising and hard to track down if you're not expecting it. Furthermore, the original tracker for this "feature" doesn't offer any ...
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Searching in a large dataset

I am working on a model of social interactions in mice. I have mice and boxes and a simulation that outputs which mouse stays in which box during which time period. The problem is how to obtain, in ...
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1answer
1k views

How best to implement a Dashboard from data in HDFS/Hadoop [closed]

We have a bunch of data (several TB) in Hadoop HDFS and it's growing. We want to create a dashboard that reports on the contents in there e.g counts of different types of objects, trends over time ...
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583 views

Text search - big data problem

I have a problem I was hoping I could get some advice on! I have a LOT of text as input (about 20GB worth, not MASSIVE but big enough). This is just free text, unstructured. I have a 'category ...
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2k views

Optimal way to store 18 billion key, value pairs [closed]

I have around 200 million new objects coming in, and a 90 day retention policy, so that leaves me with 18 billion records to be stored in the form of key-value pairs. Key and value both will be a ...
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1answer
496 views

How best to merge/sort/page through tons of JSON arrays?

Here's the scenario: Say you have millions of JSON documents stored as text files. Each JSON document is an array of "activity" objects, each of which contain a "created_datetime" attribute. What is ...
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Is it smart to design a command and control server, that will monitor system resources and spin up/spin down servers at times of peak?

I am building an application that will be modular, in a way that it will be a set of separate systems communicating with each other. It uses Hadoop on all systems, and HBase on 3 of the 4. Scaling ...
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What is the value of the Cloudera Hadoop Certification for people new to the IT industry? [closed]

I am a software developer with 8 months of experience in the IT industry, currently working on the development of tools for BIG DATA analytics. I have learned Hadoop basics on my own and I am pretty ...
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3answers
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Why do HDFS clusters have only a single NameNode?

I'm trying to understand better how Hadoop works, and I'm reading The NameNode is a Single Point of Failure for the HDFS Cluster. HDFS is not currently a High Availability system. When the ...
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Asynchronous Java

I'm wondering if I wanted to implement a web service based on java that does web analytics, what sort of architecture should I use. The actualy processing of the Big Data would be done by Hadoop. ...
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19k views

Is cloudera hadoop certification worth the investment [duplicate]

I am considering investing time to learn Hadoop and it's related technologies. The problem is that my current day job will not be using Hadoop any time soon and even if I learn from books, blogs ...
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3answers
664 views

Scalable distributed file system for blobs like images and other documents [closed]

Cassandra & HBase both do not efficiently support storage of blobs like images. Storing directly on HDFS stresses the Namenode because of huge number of files. Facebook uses Haystack for images ...
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2answers
401 views

Can Hadoop be made production-stable on a Windows platform? [closed]

Is anybody using Hadoop on Windows (Win32 or Win64) in production for serious work? If you've tried it and rejected this combination can you give your (top) reasons? If you managed to make it ...
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1answer
110 views

How do you control nodes in a server farm?

I've been reading about hadoop and multi-node setups, and it says in the documentation that you must have a JVM and hadoop software already running on those nodes. My question is, do people install ...
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962 views

Can map-reduce say “Hello World”?

Gathering that map-reduce is being used to process huge amounts of data, I set out to understand it. My queries were: What class of problems does it aim to solve? How does it help breaking down of ...
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13k views

What is Hadoop and what are some example applications of it? [closed]

The title basically says it all. I keep hearing about Hadoop, and from the wikipedia entry, it certainly sounds interesting, but I'm curious if there are some good examples where it makes sense to ...
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981 views

how to convince other we should move to hadoop?

Everything I've read about Hadoop seems like exactly the technology we need to make our enterprise more scalable. We have terabytes of raw data that is in non-relational form (text files of some ...