Details
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New Feature
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Status: Resolved
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Major
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Resolution: Fixed
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None
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None
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None
Description
Provide support for update to move directories/files atomically by copying the src directory to a tmp directory (with random/unique name) then move the directory to its target destination name after all subdirs/files are copied and verified.
example option ideas
hadoop ... distcp -update -move src dst
or
hadoop ... distcp -update -atomic src dst
to assure file correctness at the destination, before distcp performs the 'move' at the end of the copy process, it should first perform a strong signature/cksum (e.g. MD4) on the files.
The issue/need for this is that applications may attempt to start processing data (because files are present), prior to completion of a whole directory copy – resulting in work against an incomplete data set.