How to copy data from one HDFS to another HDFS

Question

I have two HDFS setup and want to copy  not migrate or move  some tables from HDFS1 to HDFS2  How to copy data from one HDFS to another HDFS  Is it possible via Sqoop or other command line

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It s also useful to note that you can run the underlying MapReduce jobs with either the source or target cluster like so   hadoop --config  path to hadoop config distcp  lt src gt   lt dst gt

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Hadoop comes with a useful program called distcp for copying large amounts of data to and from Hadoop Filesystems in parallel  The canonical use case for distcp is for transferring data between two HDFS clusters  If the clusters are running identical versions of hadoop  then the hdfs scheme is appropriate to use     hadoop distcp hdfs   namenode1 foo hdfs   namenode2 bar   The data in  foo directory of namenode1 will be copied to  bar directory of namenode2  If the  bar directory does not exist  it will create it  Also we can mention multiple source paths   Similar to rsync command  distcp command by default will skip the files that already exist  We can also use -overwrite option to overwrite the existing files in destination directory  The option -update will only update the files that have changed     hadoop distcp -update hdfs   namenode1 foo hdfs   namenode2 bar foo   distcp can also be implemented as a MapReduce job where the work of copying is done by the maps that run in parallel across the cluster  There will be no reducers   If trying to copy data between two HDFS clusters that are running different versions  the copy will process will fail  since the RPC systems are incompatible  In that case we need to use the read-only HTTP based HFTP filesystems to read from the source  Here the job has to run on destination cluster     hadoop distcp hftp   namenode1 50070 foo hdfs   namenode2 bar   50070 is the default port number for namenode s embedded web server

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distcp command use for copying from one cluster to another cluster in parallel  You have to set the path for namenode of src and path for namenode of dst  internally it use mapper   Example     hadoop distcp  lt src gt   lt dst gt    there few options you can set for distcp   -m for no  of mapper for copying data this will increase speed of copying   -atomic for auto commit the data   -update will only update data that is in old version   There are generic command for copying files in hadoop are -cp and -put but they are use only when the data volume is less

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DistCp  distributed copy  is a tool used for copying data between clusters  It uses MapReduce to effect its distribution  error handling and recovery  and reporting  It expands a list of files and directories into input to map tasks  each of which will copy a partition of the files specified in the source list   Usage    hadoop distcp  lt src gt   lt dst gt   example    hadoop distcp hdfs   nn1 8020 file1 hdfs   nn2 8020 file2  file1 from nn1 is copied to nn2 with filename file2   Distcp is the best tool as of now  Sqoop is used to copy data from relational database to HDFS and vice versa  but not between HDFS to HDFS   More info     http   hadoop apache org docs r1 2 1 distcp html http   hadoop apache org docs r1 2 1 distcp2 html   There are two versions available - runtime performance in distcp2 is more compared to distcp

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Try dtIngest  it s developed on top of Apache Apex platform  This tool copies data from different sources like HDFS  shared drive  NFS  FTP  Kafka to different destinations  Copying data from remote HDFS cluster to local HDFS cluster is supported by dtIngest  dtIngest runs yarn jobs to copy data in parallel fashion  so it s very fast  It takes care of failure handling  recovery etc  and supports polling directories periodically to do continious copy   Usage  dtingest  OPTION     SOURCEURL    DESTINATIONURL example  dtingest hdfs   nn1 8020 source hdfs   nn2 8020 dest

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distcp is used for copying data to and from the hadoop filesystems in parallel  It is similar to the generic hadoop fs -cp command  In the background process  distcp is implemented as a MapReduce job where mappers are only implemented for copying in parallel across the cluster   Usage    copy one file to another    hadoop distcp file1 file2 copy directories from one location to another    hadoop distcp dir1 dir2   If dir2 doesn t exist then it will create that folder and copy the contents  If dir2 already exists  then dir1 will be copied under it  -overwrite option forces the files to be overwritten within the same folder  -update option updates only the files that are changed    transferring data between two HDFS clusters    hadoop distcp -update -delete hdfs   nn1 dir1 hdfs   nn2 dir2   -delete option deletes the files or directories from the destination that are not present in the source

[hadoop] How to copy data from one HDFS to another HDFS?

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