hadoop admin commands

Fsck commands in Hadoop The fsck command in Hadoop can check the file in HDFS, check whether there is upt corruption or data loss, and generate the overall health report of the hdfs file system. Report content, including:Total blocks (Total number of blocks), Average block replication (Average number of copies), upt blocks, number of lost blocks,... and so on.---

1. Test the speed of Hadoop writesWrite data to the HDFs file system, 10 files, 10MB per file, files stored in/benchmarks/testdfsio/io_dataHadoop jar Share/hadoop/mapreduce/hadoop-mapreduce-client-jobclient-2.6.0-tests.jar Testdfsio-write-nrfiles 10- FileSize 10MB2. Test the speed of Hadoop read filesRead 10 files in t

Preface: Well, it's just a little bit more comfortable without writing code, but we can't slack off. The hive operation's file needs to be loaded from hereSimilar to the Linux commands, the command line begins with the Hadoop FS -(dash) LS / list file or directory cat Hadoop FS -cat ./hello.txt/opt/old/ Htt/hello.txt View files can dump directories or

success:mysql-h172.16.77.15-uroot-p123 mysql-h host address-u user name-P user PasswordView Character SetsShow variables like '%char% ';To Modify a character set:VI/ETC/MY.CNF add Default-character-set=utf8 under [client]create sudo without password loginTo set the Aboutyun user with no password sudo permissions: Chmode u+w/etc/sudoersaboutyun all= (root) nopasswd:allchmod u-w/etc/sudoers test: sudo ifconfigUbuntu View Service List codesudo service--status-allsudo initctl listTo view the file s

/ci_cuser_20141231141853691/* ' >ci_cusere_20141231141853691.csv echo $?~/.bash_profile: Each user can use this file to enter shell information dedicated to their own use, when the user logs on, theThe file is only executed once! By default, he sets some environment variables to execute the user's. bashrc file.Hadoop fs-cat ' $1$2/* ' >$3.csvMV $3.csv/home/ocdc/cocString command = "CD" + Ciftpinfo.getftppath () + "" +hadooppath+ "Hadoop fs-cat '/user

admin = new hbaseadmin (conf); Admin.disabletable ("account"); Admin.deletetable ("account"); Admin.close ();} @Testpublic void Testput () throws exception{htable table = new htable (conf, "user"); Put put = new put (Bytes.tobytes ("rk0003"));p Ut.add (bytes.tobytes ("info"), Bytes.tobytes ("name"), Bytes.tobytes (" Liuyan ")); Table.put (put); Table.close ();} @Testpublic void Testget () throws exception{htable table = new htable (conf, "user"); Get

1.hadoopView the directory on HDFs: hadoop fs-ls/ Create a directory on HDFs: -mkdir/jiatest upload the file to HDFs Specify directory: -put test.txt /Jiatest upload jar package to Hadoop run: hadoop jar maven_test-1.0-snapshot.jar org.jiahong.test.WordCount/ jiatest/jiatest/Output View result: -cat/jiatest/output/part-r-000002.linuxU

Hadoop Namenode-format formatted Distributed File systemstart-all.sh Start all Hadoop daemonsstop-all.sh Stop all Hadoop daemonsstart-mapred.sh Start the Map/reduce daemonstop-mapred.sh Stop Map/reduce DaemonStart-dfs.sh starting the HDFs daemonstop-mapred.sh Stop HDFs Daemonstart-balancer.sh HDFS data Block load BalancingFS in the following command can also be w

1.1)vim/etc/udev/rules.d/ --persistent-Net.rulesVI/etc/sysconfig/network-scripts/ifcfg-Eth0type=Ethernetuuid=57d4c2c9-9e9c-48f8-a654-8e5bdbadafb8onboot=yesnm_controlled=YesBootproto = staticDefroute=Yesipv4_failure_fatal=Yesipv6init=NoNAME="System eth0"HWADDR=xx: 0c: in: -: E6:ecipaddr =172.16.53.100PREFIX= -gateway=172.16.53.2Last_connect=1415175123dns1=172.16.53.2The virtual machine's network card is using the virtual network cardSave Exit X or Wq2)Vi/etc/sysconfig/networkNetworking=yesHostnam

From:http://www.2cto.com/database/201303/198460.htmlHadoop HDFs Common CommandsHadoop common commands:Hadoop FSView all commands supported by Hadoop HDFsHadoop fs–lslisting directory and file informationHadoop FS–LSRLoop lists directories, subdirectories, and file informationHadoop fs–put Test.txt/user/sunlightcsCopy the test.txt of the local file system to the/user/sunlightcs directory of the HDFs file sys

, soHDFs has a high degree of fault tolerance.3. High data throughput HDFs uses a "one-time write, multiple read" This simple data consistency model, in HDFS , once a file has been created, written, closed, generally do not need to modify, such a simple consistency model, to improve throughput.4. Streaming data access HDFS has a large scale of data processing, applications need to access a large amount of information at a time, and these applications are generally batch processing, rather than

Modify permissions for a file or directory Chown chown [ options ] User [ . Group ] file/dir Modify the owner of a file Chgrp Chgrp [-R] Group name Dir/file Modify the owning group of a file Iv. Systems and Networks Option name Meaning passwd xxx Change Password Df-ah View disk space Ps-ef |grep View process Kill-9 Kill the process

mytable from Database mydb to the E:\MySQL\mytable.sql file. c:\> mysqldump-h localhost-u root-p mydb mytable>e:\mysql\mytable.sql Example 3: Export the structure of the database mydb to a e:\MySQL\mydb_stru.sql file. c:\> mysqldump-h localhost-u root-p mydb--add-drop-table >e:\mysql\mydb_stru.sql Note :-h localhost can be omitted, it is generally used on the virtual host.3) Export data structure onlyformat : mysqldump-u [Database user name]-p-t [the name of the data

localhost-u root-p mydb >e:\mysql\mydb.sql Then enter the password, wait for an export to succeed, you can check the target file for success. Example 2: Export mytable from Database mydb to the E:\MySQL\mytable.sql file. c:\> mysqldump-h localhost-u root-p mydb mytable>e:\mysql\mytable.sql Example 3: Export the structure of the database mydb to a e:\MySQL\mydb_stru.sql file. c:\> mysqldump-h localhost-u root-p mydb--add-drop-table >e:\mysql\mydb_stru.sql