Kihwal Lee created HDFS-9208:
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             Summary: Disabling atime may fail clients like distCp
                 Key: HDFS-9208
                 URL: https://issues.apache.org/jira/browse/HDFS-9208
             Project: Hadoop HDFS
          Issue Type: Bug
            Reporter: Kihwal Lee


When atime is disabled, {{setTimes()}} throws an exception if the passed-in 
atime is not -1.  But since atime is 0, distCp fails when it tries to set the 
mtime and atime. 

There are several options:

1) make distCp check for 0 atime and call {{setTimes()}} with -1. I am not very 
enthusiastic about it.
2) make NN also accept 0 atime in addition to -1, when the atime support is 
disabled.
3) support setting mtime & atime regardless of the atime support.  The main 
reason why atime is disabled is to avoid edit logging/syncing during 
{{getBlockLocations()}} read calls. Explicit setting can be allowed.



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