hadoop hdfs commands

Spark program Note: This is not the final solution, so you need to find out why If the file is important, you need to fix it.View file status one by one and restoreTake this file as an example:/user/admin/data/cdn//20170508/ngaahcs-access.log.3k3.201705081700.1494234003128.gz To perform a repair command: HDFs Debug Recoverlease-path HDFs Debug Recoverlease-path/user/admin/data/cdn//20170508/ngaahcs-acces

-level or T-level, so HDFs needs to be able to support large files. There is also a need to support storing a large number of files in one instance (It should tens of millionsof files in A and a single instance).4. Data Consistency Assurance: HDFS needs to be able to support the "Write-once-read-many access" model.In the face of the above architectural requirements, let's look at how

5) The Java InterfaceA) Reading Data from a Hadoop URL.Using the Hadoop URL to read datab) Although we focus mainly on the HDFS implementation, Distributedfilesystem, in general you should strive to write your Code against the FileSystem abstract class, to retain portability across filesystems.While we focus primarily on the implementation of

Reprinted please indicate the source, http://blog.csdn.net/lastsweetop/article/details/9001467 All source code on GitHub, https://github.com/lastsweetop/styhadoopReading data using hadoop URL is a simple way to read HDFS data through java.net. the URL opens a stream, but before that, you must call its seturlstreamhandlerfactory method to set it to fsurlstreamhandlerfactory (the factory retrieves the parsing

first, the purpose of the experiment1. There is only one namenode for the existing Hadoop cluster, and a namenode is now being added.2. Two namenode constitute the HDFs Federation.3. Do not restart the existing cluster without affecting data access.second, the experimental environment4 CentOS Release 6.4 Virtual machines with IP address192.168.56.101 Master192.168.56.102 slave1192.168.56.103 Slave2192.168.5

/lib/eclipsehttp://www.blogjava.net/hongjunli/archive/2007/08/15/137054.html troubleshoot viewing. class filesA typical Hadoop workflow generates data files (such as log files) elsewhere, and then copies them into HDFs, which is then processed by MapReduce. Typically, an HDFs file is not read directly. They rely on the MapReduce framework to read. and resolves it

HDFs system architecture Diagram level analysis Hadoop Distributed File System (HDFS): Distributed File systems * Distributed applications mainly from the schema: Master node Namenode (one) from the node: Datenode (multiple) *HDFS Service Components: Namenode,datanode,secondarynamenode *

Hadoop HDFS Tools PackageCN.BUAA;ImportJava.io.ByteArrayOutputStream;ImportJava.io.IOException;ImportJava.io.InputStream;ImportOrg.apache.hadoop.conf.Configuration;ImportOrg.apache.hadoop.fs.FSDataOutputStream;ImportOrg.apache.hadoop.fs.FileStatus;ImportOrg.apache.hadoop.fs.FileSystem;ImportOrg.apache.hadoop.fs.Path;ImportOrg.apache.hadoop.fs.RemoteIterator;ImportOrg.apache.hadoop.io.IOUtils;/ * * @author L

recognize IP must have JDK1.7, and JDK environment variables must be configured well. Configuration environment variable: VI ~/.bash_profile #全局变量:/etc/profile at the end of the file add: Export Java_home=/usr/java/default export path= $PATH: $JAVA _ Home/bin source ~/.bash_profile Refresh environment variable file firewall temporarily shut down. Upload tar and unzip (TAR-ZXVF tar package name). and configure the environment variable of HADOOP export

This article uses the hadoop Source Code. For details about how to import the hadoop source code to eclipse, refer to the first phase. I. background of HDFS As the amount of data increases, the data cannot be stored within the jurisdiction of an operating system, so it is allocated to more disks managed by the operating system, but it is not convenient to manag