hadoop fs commands

region:#hbase> major_compact ‘r1‘, ‘c1‘#Compact a single column family within a table:#hbase> major_compact ‘t1‘, ‘c1‘ Configuration Management and node restart1) Modify the HDFs configurationHDFs Configuration Location:/etc/hadoop/conf # 同步hdfs配置cat /home/hadoop/slaves|xargs -i -t scp /etc/hadoop/conf/hdfs-site.x

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

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

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

, 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

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 get = new Get (Bytes.tobytes ("rk0001")); Ge

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