hadoop material

1. What is a distributed file system?A file system that is stored across multiple computers in a management network is called a distributed file system.2. Why do I need a distributed file system?The simple reason is that when the size of a dataset exceeds the storage capacity of a single physical computer, it is necessary to partition it (partition) and store it on several separate computers.3. Distributed systems are more complex than traditional file systemsBecause the Distributed File system

1. Introduction to Hadoop versionConfiguration files that were previously in the 0.20.2 version (without this version) are in Default.xml.The 0.20.x version does not contain the Eclipse plug-in jar package, because the eclipse version is different, so you need to compile the source code to generate the corresponding plug-in.The 0.20.2--0.22.x version of the configuration file is centralized in conf/core-site.xml, conf/hdfs-site.xml , and conf/mapred-s

01_note_hadoop introduction of source and system; Hadoop cluster; CDH FamilyUnzip Tar Package Installation JDK and environment variable configurationTAR-XZVF jdkxxx.tar.gz to/usr/app/(custom app to store the app after installation)Java-version View current system Java version and environmentRpm-qa | grep Java View installation packages and dependenciesYum-y remove xxxx (remove grep out of each package)Configure the environment variable/etc/profile, an

A few days ago, I summarized the hadoop distributed cluster installation process. Building a hadoop cluster is only a difficult step in learning hadoop. More knowledge is needed later, I don't know if I can stick to it or how many difficulties will be encountered in the future. However, I think that as long as I work hard, the difficulties will always be solved.

Fedora20 installation hadoop-2.5.1, hadoop-2.5.1 First of all, I would like to thank the author lxdhdgss. His blog article directly helped me install hadoop. Below is his revised version for jdk1.8 installed on fedora20. Go to the hadoop official website to copy the link address (hadoop2.5.1 address http://mirrors.cnni

1. Create a userAddUser HDUserTo modify HDUser user rights:sudo vim/ect/sudoers, add HDUser all= (All:all) all in the file.　　2. Install SSH and set up no password login1) sudo apt-get install Openssh-server2) Start service: SUDO/ETC/INIT.D/SSH start3) Check that the service is started correctly: Ps-e | grep ssh　　4) Set password-free login, generate private key and public keySsh-keygen-t rsa-p ""Cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys　　5) Password-free login: ssh localhost6) Exit3. Config

The first 2 blog test of Hadoop code when the use of this jar, then it is necessary to analyze the source code. It is necessary to write a wordcount before analyzing the source code as follows Package mytest; Import java.io.IOException; Import Java.util.StringTokenizer; Import org.apache.hadoop.conf.Configuration; Import Org.apache.hadoop.fs.Path; Import org.apache.hadoop.io.IntWritable; Import Org.apache.hadoop.io.Text; Import Org.apache.hadoop.map

VirtualBox build Pseudo-distributed mode: Hadoop Download and configurationAs a result of personal machine slightly slag, unable to deploy Xwindow environment, direct use of the shell to operate, want to use the mouse to click the operation of the left do not send ~1.hadoop Download and decompressionhttp://mirror.bit.edu.cn/apache/hadoop/common/stable2/

there is no interference between them too much.g) The first problem to solve are hardware failure:as soon as you start using many pieces of hardware, the chance that one Would fail is fairly high.The first problem to solve is a hardware failure problem: As long as you use a multi-part integrated device, there is a very high chance that one of the parts will fail.h) The second problem is a most analysis of the tasks need to being able to combine the data in some a, and data read from one Disk ma

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