hadoop copy directory from hdfs to hdfs

Hadoop hdfs cannot be restarted after the space is full. hadoophdfs When the server checks, it finds that files on HDFS cannot be synchronized and hadoop is stopped. Restart failed. View hadoop logs: 2014-07-30 14:15:42,025 INFO org.apache.hadoop.hdfs.server.namenode.FSNa

Hadoop's HDFs clusters are prone to unbalanced disk utilization between machines and machines, such as adding new data nodes to a cluster. When there is an imbalance in HDFs, there are a lot of problems, such as the Mr Program does not take advantage of local computing, the machine is not able to achieve better network bandwidth utilization, the machine disk can not be used and so on. It is important to ens

ObjectiveWhen we are using HDFS, sometimes we need to do some temporary data copy operation, if it is in the same cluster, we directly with the internal HDFS CP command, if it is cross-cluster or when the amount of data to be copied is very large size, We can also use the Distcp tool. But does this mean that we use these tools to still be efficient when copying d

A Hadoop HDFs operation class Package com.viburnum.util; Import Java.net.URI; Import Java.text.SimpleDateFormat; Import Java.util.Date; Import java.io.*; Import org.apache.hadoop.conf.Configuration; Import org.apache.hadoop.fs.BlockLocation; Import Org.apache.hadoop.fs.FSDataInputStream; Import Org.apache.hadoop.fs.FSDataOutputStream; Import Org.apache.hadoop.fs.FileStatus; Import Org.apache.hadoop.fs.Fi

Hadoop version: 2.6.0This article is from the Official document translation, reproduced please respect the work of the translator, note the following links:Http://www.cnblogs.com/zhangningbo/p/4146398.htmlOverviewCentralized cache management in HDFs is an explicit caching mechanism that allows the user to specify the HDFs path to cache. Namenode will communicate

Write more verbose, if you are eager to find the answer directly to see the bold part of the .... (PS: What is written here is all the content in the official document of the 2.5.2, the problem I encountered when I did it) When you execute a mapreduce job locally, you encounter the problem of No such file or directory, follow the steps in the official documentation: 1. Formatting Namenode Bin/hdfs Namenode-format 2. Start the Namenode and Datanod

What is 1.HDFS?The Hadoop Distributed File System (HDFS) is designed to be suitable for distributed file systems running on general-purpose hardware (commodity hardware). It has a lot in common with existing Distributed file systems.Basic Concepts in 2.HDFS(1) blocks (block)"Block" is a fixed-size storage unit,

Configuration file m103 Replace with the HDFs service address.To use the Java client to access the file on the HDFs, have to say is the configuration file Hadoop-0.20.2/conf/core-site.xml, originally I was here to eat a big loss, so I am not even hdfs, file can not be created, read. Configuration item: H

4th Chapter HDFs java API 4.5 Java API Introduction In section 4.4 We already know the HDFs Java API configuration, filesystem, path, and other classes, this section will detail the HDFs Java API, a section to demonstrate more applications. 4.5.1 Java API website Hadoop 2.7.3 Java API official addressHttp://hadoop.ap

Data integrity IO operation process will inevitably occur data loss or dirty data, data transmission of the greater the probability of error. Checksum error is the most commonly used method is to calculate a checksum before transmission, after transmission calculation of a checksum, two checksum if not the same data exist errors, more commonly used error check code is CRC32. HDFs Data integrity The checksum is computed when the

[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 or

1. The purpose of this articleUnderstand some of the features and concepts of the HDFS system for Hadoop by parsing the client-created file flow.2. Key Concepts2.1 NameNode (NN)：HDFs System core components, responsible for the Distributed File System namespace management, Inode table file mapping management. If the backup/recovery/federation mode is not turned on

This article was posted on my blog This time to see how our clients connect Jobtracker with URLs. We've built a pseudo-distributed environment and we know the address. Now we look at the files on HDFs, such as address: Hdfs://hadoop-master:9000/data/test.txt. Look at the following code: Static final String PATH = "Hdfs