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Rosie Li commented on MAPREDUCE-2257: ------------------------------------- FileChunkPair is still src/dst file pairs but with the other 3 fields telling the starting point and offset for the file chunk pairs Also I merged doCopyFile() and doCopyFileChunks(), now we only have one doCopyFile method. > distcp can copy blocks in parallel > ---------------------------------- > > Key: MAPREDUCE-2257 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-2257 > Project: Hadoop Map/Reduce > Issue Type: Improvement > Components: distcp > Affects Versions: 0.21.0 > Reporter: dhruba borthakur > Assignee: dhruba borthakur > Attachments: MAPREDUCE-2257.patch > > > The minimum unit of work for a distcp task is a file. We have files that are > greater than 1 TB with a block size of 1 GB. If we use distcp to copy these > files, the tasks either take a long long long time or finally fails. A better > way for distcp would be to copy all the source blocks in parallel, and then > stich the blocks back to files at the destination via the HDFS Concat API > (HDFS-222) -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira