Currently in Hadoop used more than lzo,gzip,snappy,bzip2 these 4 kinds of compression format, the author based on practical experience to introduce the advantages and disadvantages of these 4 compression formats and application scenarios, so that we in practice according to the actual situation to choose different compression format.
1 gzip compression
Advantages: The compression ratio is high, and the compression/decompression speed is relatively fas
to facilitate the MapReduce direct access to the relational database (mysql,oracle). Hadoop offers two classes of Dbinputformat and Dboutputformat. Through the Dbinputformat class, the database table data is read into HDFs, and the result set generated by MapReduce is imported into the database table according to the Dboutputformat class.error when executing mapreduce: java.io.IOException:com.mysql.jdbc.Driver, usually because the program cannot find
First, compile the Hadoop pluginFirst you need to compile the Hadoop plugin: Hadoop-eclipse-plugin-2.6.0.jar Before you can install it. Third-party compilation tutorial: Https://github.com/winghc/hadoop2x-eclipse-pluginIi. placing plugins and restarting eclipsePut the compiled plugin Hadoop-eclipse-plugin-2.6.0.jar int
Basic Hadoop tutorial
This document uses the Basic Environment configuration of the K-Master server as an example to demonstrate user configuration, sudo permission configuration, network configuration, firewall shutdown, and JDK installation. Follow these steps to complete KVMSlave1 ~ The Basic Environment configuration of the KVMSlave3 server.Development Environment
Hardware environment: Four CentOS 6.5 servers (one Master node and three Slave node
Hadoop learning notes-installation in full distribution mode
Steps for installing hadoop in fully distributed mode
Hadoop mode Introduction
Standalone mode: easy to install, with almost no configuration required, but only for debugging purposes
Pseudo-distribution mode: starts five processes, including namenode, datanode, jobtracker, tasktracker, and seco
Construction and management of Hadoop environment on CentOSPlease load the attachmentDate of compilation: September 1, 2015Experimental requirements:Complete the Hadoop platform installation deployment, test the Hadoop platform capabilities and performance, record the experiment process, and submit the lab report.1) Mastering the
High-availability Hadoop platform-Hadoop Scheduling for Oozie Workflow1. Overview
In the "high-availability Hadoop platform-Oozie Workflow" article, I will share with you how to integrate a single plug-in such as Oozie. Today, we will show you how to use Oozie to create related workflows for running and Hadoop. You mu
Several Hadoop daemon and Hadoop daemon
After Hadoop is installed, several processes will appear when jps is used.
Master has:
Namenode
SecondaryNameNode
JobTracker
Slaves has
Tasktracker
Datanode
1.NameNode
It is the master server in Hadoop, managing the file system namespace and accessing the files stored in the
resourcesMaster-Slave structureMaster node, there can be 2: ResourceManagerFrom the node, there are a number of: NodeManagerResourceManager is responsible for:Allocation and scheduling of cluster resourcesFor applications such as MapReduce, Storm, and Spark, the Applicationmaster interface must be implemented to be managed by RMNodeManager is responsible for:Management of single node resourcesVII: The architecture of MapReduceBatch computing model with disk IO dependentMaster-Slave structureMas
Big data: Massive dataStructured data: Data that can be stored in a two-dimensional tableunstructured data: Data cannot be represented using two-dimensional logic of the data. such as word,ppt, picture Semi-structured data: a self-describing, structured and unstructured data that stores the structure with the data itself: XML, JSON, HTMLGoole paper: mapreduce:simplified Date processing on Large Clusters Map: Small data that maps big data to multiple nodes that are segmented
First on the correct run display:Error 1: The variable is intwritable and is receiving longwritable, such as:Reason, write more parameters reporter, such as:Error 2: The array is out of bounds, such as:Cause: The Combine class is set up, such as:Error 3:nullpointerexception exception, such as:Cause: The static variable is null and can be assigned, such as:Error 4: Entering map, but unable to enter reduce, and direct map data output, and no error promptCause: The new and older version of
1 access to Apache Hadoop websitehttp://hadoop.apache.org/2.2. Click image to downloadWe download the 2.6.0 third in the stable version of stableLinux Download , here is an error, we download should be the bottom of the second, which I did not pay attention to download the above 17m .3. Install a Linux in the virtual machineFor details see other4. Installing the Hadoop environment in Linux1. Installing the
Hadoop Elephant Safari 010- using Eclipse to view Hadoop source code sinomThis is what I'm using. hadoop-1.1.2.tar.gz , this file can be downloaded at the following address:Official Address: http://archive.apache.org/dist/hadoop/core/hadoop-1.1.2/1. Unzip the
Reprint Please specify source: http://blog.csdn.net/l1028386804/article/details/51538611
The following warning message appears when you configure Hadoop to start:
WARN util. nativecodeloader:unable to load Native-hadoop library for your platform ... using Builtin-java classes where applicableThe question is where. Some people say that this is the pre-compiled Hadoop
This is a major chat about Hadoop Distributed File System-hdfs
Outline:
1.HDFS Design Objectives
The Namenode and Datanode inside the 2.HDFS.
3. Two ways to operate HDFs 1.HDFS design target hardware error
Hardware errors are normal rather than abnormal. (Every time I read this I think: programmer overtime is not abnormal) HDFs may consist of hundreds of servers, each of which stores part of the file system's data. The reality we face is that the numb
Run Hadoop WordCount. jar in Linux.
Run Hadoop WordCount in Linux
Enter the shortcut key of Ubuntu terminal: ctrl + Alt + t
Hadoop launch command: start-all.sh
The normal execution results are as follows:
Hadoop @ HADOOP :~ $ Start-all.sh
Warning: $ HADOOP_HOME is deprecate
This article introduces a highly automatic RedHatLinux Installation Method in CentOS unattended installation Based on KickstartPXE. Because Kickstart supports scripts, Kickstart technology can also be used to automate the deployment of Hadoop clusters. This article tries to build a method to automatically deploy the Hadoop Cluster Based on the Resource Allocation file using the Kickstart script.
This articl
Once Hadoop is installed, you will often be prompted with a warning:
WARN util. nativecodeloader:unable to load Native-hadoop library for your platform ...
Using Builtin-java classes where applicableSearched a lot of articles, all say is related to the system bit number, I use CentOS 6.5 64-bit operating system.
The first two days in the Docker image to find a step to solve the problem, the pro tried
Hadoop standalone pseudo-distributed deployment
Because there are not so many machines, we can deploy a Hadoop cluster on our own virtual machine. This is called a pseudo-distributed cluster. However, in any case, we mainly record the hadoop deployment process and problems, then use a simple program testing environment.
1. install JAVA, download the
Exception Analysis
1. "cocould only be replicated to 0 nodes, instead of 1" Exception
(1) exception description
The configuration above is correct and the following steps have been completed:
[Root @ localhost hadoop-0.20.0] # bin/hadoop namenode-format
[Root @ localhost hadoop-0.20.0] # bin/start-all.sh
At this time, we can see that the five processes jobtracke
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