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https://issues.apache.org/jira/browse/HDFS-9208?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kihwal Lee updated HDFS-9208:
-----------------------------
    Description: 
When atime is disabled, {{setTimes()}} throws an exception if the passed-in 
atime is not -1.  But since atime is not -1, 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.

  was:
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.


> 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
>            Assignee: Mingliang Liu
>
> When atime is disabled, {{setTimes()}} throws an exception if the passed-in 
> atime is not -1.  But since atime is not -1, 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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