Alibabacloud.com offers a wide variety of articles about hadoop copy directory from hdfs to hdfs, easily find your hadoop copy directory from hdfs to hdfs information here online.
Install times wrong: Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.7:run (site) on project Hadoop-hdfs:an Ant B Uildexception has occured:input file/usr/local/hadoop-2.6.0-stable/hadoop-2.6.0-src/hadoop-hdfs-project/
"), also add our standard Spark classpath, built using compute-classpath.sh.
Classpath= ' $FWDIR/bin/compute-classpath.sh '
Classdata-path= "$SPARK _qiutest_jar: $CLASSPATH"
# find Java Binary
If [-N "${java_home}"]; Then
Runner= "${java_home}/bin/java"
Else
If [' command-v Java ']; Then
Runner= "Java"
Else
echo "Java_home is not set" >2
Exit 1
Fi
Fi
If ["$SPARK _print_launch_command" = = "1"]; Then
Echo-n "Spark Command:"
echo "$RUNNER"-CP "$CLASSPATH" "$@"
echo "=============================
now let's take a closer look at the FileSystem class for Hadoop. This class is used to interact with Hadoop's file system. While we are mainly targeting HDFS here, we should let our code use only abstract class filesystem so that our code can interact with any Hadoop file system. When we write the test code, we can test it with the local file system, use
Multiple interfaces are available to access HDFS. The command line interface is the simplest and the most familiar method for programmers.
In this example, HDFS in pseudo sodistributed mode is used to simulate a distributed file system. For more information about how to configure the pseudo-distributed mode, see configure:
This means that the default file system of hado
requireHdfs-site.xml configuration (multiple Namenode)Formatting multiple NamenodeHDFs Namenode-format[-clusterid HDFs Namenode-format-clusterid 2.x supports multiple namenode to distribute load and achieve performance assuranceNamespace Management-Client Side Mount TableAdd a new Datanode nodeInstall Hadoop on new datanode and copy config from NamenodeUpdate Ma
store, and does not have to worry about the storage of file metadata, because the block only stores data, the object metadata (such as permissions) is stored on an independent computer and operated independently. In addition, Block Storage facilitates fault tolerance. To ensure that data will not be lost when any storage node fails, data is generally backed up by block. Generally, blocks on one machine are backed up on the other two machines, that is, there are three copies in total. If the dat
Label: style blog HTTP color Io Java strong SP File
Copy Mechanism
1. Copy placement policy
The first copy is placed on the datanode of the uploaded file. If it is submitted outside the cluster, a node with a low disk speed and a low CPU usage will be randomly selected;The second copy is placed on nodes in differ
and directory name, and uses the FileStatus object to store the metadata of the file and directory. Use the listStatus () method to obtain the file list in a directory:
Path inputDir = new Path (args [0]);
FileStatus [] inputFiles = local. listStatus (inputDir );
The length of the array inputFiles is equal to the number of files in the specified directory. In inputFiles, each FileStatus object has metadata information, such as the file length, permission, and modification time.
You can use the
Sudo addgroup hadoop # Add a hadoop GroupSudo usermod-a-g hadoop Larry # Add the current user to the hadoop GroupSudo gedit ETC/sudoers # Add the hadoop group to sudoerHadoop all = (all) All after root all = (all) All
Modify hadoop
communicating with Datanode, it tries to get the current block data from the next closest Datanode node. The Dfsinputstream also logs the Datanode node where the error occurred so that it does not attempt to go to those nodes later when the block data is read. Dfsinputstream will also do checksum check after reading the block data on Datanode, if checksum fails, it will first report the data on this namenode to Datanode. Then try a datanode with the current block. in this set of design, the mos
Add a Hadoop group
sudo addgroup Hadoop
Add the current user Larry to the Hadoop groupsudo usermod-a-G Hadoop Larry
Add Hadoop Group to Sudoersudo gedit etc/sudoersHadoop all= (All) after Root all= (all)
Modify the permissions for the H
HDFS file system provides an API for an abstract File System Based on hadoop, which supports stream-based access to data in the file system.Features:1. Support for ultra-large files2. Detect and quickly respond to hardware faults (fault detection and Automatic Recovery)3. Streaming Data Access focuses on data throughput rather than data response speed4. Simplified consistency model with one write and multip
Not much to say, directly on the code.CodePackage zhouls.bigdata.myWholeHadoop.HDFS.hdfs5;Import java.io.IOException;Import Java.net.URI;Import java.net.URISyntaxException;Import org.apache.hadoop.conf.Configuration;Import Org.apache.hadoop.fs.FileSystem;Import Org.apache.hadoop.fs.Path;/**** @author* @function Copying from the Local file system to HDFS**/public class Copyinglocalfiletohdfs{/*** @function Main () method* @param args* @throws IOExcepti
Introduction
Prerequisites and Design Objectives
Hardware error
Streaming data access
Large data sets
A simple consistency model
"Mobile computing is more cost effective than moving data"
Portability between heterogeneous software and hardware platforms
Namenode and Datanode
File System namespace (namespace)
Data replication
Copy storage: One of the most starting steps
Not much to say, directly on the code.CodePackage zhouls.bigdata.myWholeHadoop.HDFS.hdfs7;Import java.io.IOException;Import Java.net.URI;Import java.net.URISyntaxException;Import org.apache.hadoop.conf.Configuration;Import Org.apache.hadoop.fs.FSDataInputStream;Import Org.apache.hadoop.fs.FSDataOutputStream;Import Org.apache.hadoop.fs.FileStatus;Import Org.apache.hadoop.fs.FileSystem;Import Org.apache.hadoop.fs.FileUtil;Import Org.apache.hadoop.fs.Path;Import Org.apache.hadoop.fs.PathFilter;Impo
-cp/user/hadoop/file1/user/hadoop/file2 Hadoop fs-cp/user/hadoop/file1/user/hadoop/file2/user/hadoop/ Dir
return value:
Successfully returns 0, failure returns-1. du
How to use: Hadoop
1. Problem: When the input of a mapreduce program is a lot of mapreduce output, since input defaults to only one path, these files need to be merged into a single file. This function copymerge is provided in Hadoop.
The function is implemented as follows:
public void Copymerge (string folder, string file) {
path src = new Path (folder);
Path DST = new path (file);
Configuration conf = new configuration ();
try {
Fileutil.copymerge (src.g
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.