hdfs commands

Objective:Learn the configuration of Windows development Hadoop programs.[0007] Example of an Eclipse development HDFs program under WindowsToo much trouble[0010] Windows Eclipse Development HDFS Program sample (II)Output log changes, and configuration seems to be cumbersome.Environment:Windows 7 64 under EclipseDescriptionThis practice was made after the [0008] Windows 7 Hadoop 2.6.4 Eclipse Local Developm

HDFS Core Principle2016-01-11 Du Yishu HDFS (Hadoop Distribute file system) is a distributed filesystemThe file system is the disk space management service provided by the operating system, we only need to specify where to put the file, from which path to read the file sentence, do not care about how the file is stored on diskWhat happens when the file requires more space than the native disk space?One is t

The HDFS (Hadoop Distributed File System) is one of the core components of Hadoop and is the basis for data storage management in distributed computing, and is designed to be suitable for distributed file systems running on common hardware. HDFS architecture has two types of nodes, one is Namenode, also known as "meta-data Node", the other is Datanode, also known as "Data Node", respectively, to perform the

a disk has its block size, which represents the minimum amount of data it can read and write. The file system operates this disk by processing chunks of integer multiples of the size of a disk block. The file system block is typically thousands of bytes, and the disk block is generally a byte. This information is transparent to file system users who simply read or write at any length on a single file. However, some tools maintain file systems, such as DF and fsck, which operate at the system bl

Re-understanding the storage mechanism of HDFS1. HDFs pioneered the design of a set of file storage methods, namely, the separation of files after the storage;2. HDFs will be stored in the large file segmentation, the partition is stored in the established storage block (block), and through the pre-set optimization processing, the mode of the stored data preprocessing, thus solving the large file storage an

About HDFSThe Hadoop Distributed file system, referred to as HDFs, is a distributed filesystem. HDFs is highly fault-tolerant and can be deployed on low-cost hardware, and HDFS provides high-throughput access to application data, which is suitable for applications with large data sets. It has the following characteristics:1) suitable for storing very large files2

configuring CDH and Managing servicesTuning of HDFs before closing DatanodeRole requirements: Configurator, Cluster Administrator, full Administratorwhen a datanode is closed, Namenode ensures that each block in each Datanode is still available based on the replication factor (the replication factor) across the cluster. This process involves the block duplication of small batches between datanode. In this case, a datanode has thousands of blocks, and

Original link: http://blog.csdn.net/ashic/article/details/47068183Official Document Link: http://hadoop.apache.org/docs/r2.7.1/hadoop-project-dist/hadoop-hdfs/HdfsSnapshots.htmlOverviewThe HDFs snapshot is a read-only, point-in-time file system copy. You can take a snapshot of a subdirectory in the file system or the entire file system. Snapshots are often used as data backups to prevent user errors and dis

Hdfs-hadoop File SystemSection One: The file structure of HDFsLearning HDFs first needs to understand the file structure of HDFs, and how it updates and saves the data, to understand HDFs first to know that HDFs is mainly composed of three parts: Namenode,datanode,secondaryn

, for subsequent data mining and analysis. The data is collected to HDFS and a file is generated on a regular basis every day (the file prefix is the date, and the suffix is the serial number starting from 0). When the file size exceeds the specified size, A new file is automatically generated. The file prefix is the current date, And the suffix is the current serial number. The system running architecture diagram and related descriptions are as follo

Architecture The image shows that HDFS mainly contains the following functional components:Namenode: stores the metadata of a document and the directory structure of the entire file system.Datanode: stores document block information, and there is redundant backup between document blocks.The document block concept is mentioned here. Like the local file system, HDFS is also block-based storage, but the block

[Flume] uses Flume to pass the Web log to HDFs example:Create the directory where log is stored on HDFs:$ HDFs dfs-mkdir-p/test001/weblogsflumeSpecify the log input directory:$ sudo mkdir-p/flume/weblogsmiddleSettings allow log to be accessed by any user:$ sudo chmod a+w-r/flume$To set the configuration file contents:$ cat/mytraining/exercises/flume/spooldir.conf

[TOC] Hadoop HDFS Java APIMainly Java operation HDFs Some of the common code, the following direct code:Package Com.uplooking.bigdata.hdfs;import Org.apache.hadoop.conf.configuration;import org.apache.hadoop.fs.*; Import Org.apache.hadoop.fs.permission.fspermission;import Org.apache.hadoop.io.ioutils;import org.junit.After; Import Org.junit.before;import org.junit.test;import Java.io.bufferedreader;im

console log4j.appender.systemout= org.apache.log4j.ConsoleAppender log4j.appender.systemout.layout= Org.apache.log4j.PatternLayout log4j.appender.systemout.layout.conversionpattern= [%-5p][%-22d{yyyy/mm/dd HH : mm:sss}][%l]%n%m%n log4j.appender.systemout.threshold= INFO log4j.appender.systemout.immediateflush= TRUE Finally, copy and paste five profiles of Hadoop into the src\main\resources directory iii. Java API operation HDFs Client to opera

Label:Recently in the use of sqoop1.99.6 to do data extraction, during the encounter a lot of problems, hereby recorded here, convenient for later review and collation 1. First configuration, you need to configure the Lib directory of HDFs to Catalina.properties Common.loader=${catalina.base}/lib,${catalina.base}/lib/*.jar,${catalina.home}/lib,${catalina.home}/lib/*.jar, ${catalina.home}/. /lib/*.jar,/usr/lib/hadoop/*.jar,/usr/lib/hadoop/lib/*.jar,/us

Name Value Description DFS. Default. Chunk. View. Size 32768 The size of each file displayed on the HTTP access page of namenode usually does not need to be set. DFS. datanode. Du. Reserved 1073741824 The size of the space reserved by each disk, which must be set to be used mainly for non-HDFS files. The default value is not reserved, and the value is 0 bytes. DFS. Name. dir /Opt/data1/

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 Slave2192.168.56.104 KettleOne of the kettle is a new "clean

PackageCn.itcast.bigdata.hdfs;ImportJava.net.URI;ImportJava.util.Iterator;ImportJava.util.Map.Entry;Importorg.apache.hadoop.conf.Configuration;ImportOrg.apache.hadoop.fs.FileStatus;ImportOrg.apache.hadoop.fs.FileSystem;ImportOrg.apache.hadoop.fs.LocatedFileStatus;ImportOrg.apache.hadoop.fs.Path;ImportOrg.apache.hadoop.fs.RemoteIterator;ImportOrg.junit.Before;Importorg.junit.Test;/*** * Client to operate HDFS, there is a user identity * By default, the

1. Directory Quota [xiaoqiu@s150/home/xiaoqiu/hadoop_tmp]$ Hadoop FS-LSR/ lsr:DEPRECATED:Please use ' ls-r ' instead. Drwxr-xr-x -Xiaoqiu supergroup 0 2017-12-29 15:50/user drwxr-xr-x -Xiaoqiu supergroup 0 2017-12-29 15:50/user/xiaoqiu drwxr-xr-x -xiaoqiu supergroup 0 2017-12-29 15:50/user/xiaoqiu/data drwxr-xr-x -xiaoqiu supergroup 0 2017-12-29 15:44/usr drwxr-xr-x -Xiaoqiu supergroup 0 2017-12-29 15:44/usr/xiaoqiu drwxr-xr-x -xiaoqiu sup

Preparatory work: 1, install the Hadoop; 2. Create a Helloworld.jar package, this article creates a jar package under the Linux shell: Writing Helloworld.java filespublic class HelloWorld{public static void Main (String []args) throws Exception{System.out.println ("Hello World");} } Javac Helloworld.java is compiled and gets Helloworld.classIn the catalogue CV MANIFEST.MF file:manifest-version:1.0CREATED-BY:JDK1.6.0_45 (Sun Microsystems Inc.)Main-class:helloworld Run command: Jar CVFM Hellowor