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https://issues.apache.org/jira/browse/HADOOP-16085?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16758736#comment-16758736
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Andrew Olson commented on HADOOP-16085:
---------------------------------------

[~mackrorysd] Looks like it's possible to create a [bucket lifecycle 
rule|https://docs.aws.amazon.com/AmazonS3/latest/user-guide/create-lifecycle.html]
 to automatically purge out old object versions after some specified expiration 
time, which would be helpful to keep the S3 space from indefinitely growing if 
the same file paths are being continually overwritten.

> S3Guard: use object version to protect against inconsistent read after 
> replace/overwrite
> ----------------------------------------------------------------------------------------
>
>                 Key: HADOOP-16085
>                 URL: https://issues.apache.org/jira/browse/HADOOP-16085
>             Project: Hadoop Common
>          Issue Type: Sub-task
>          Components: fs/s3
>    Affects Versions: 3.2.0
>            Reporter: Ben Roling
>            Priority: Major
>         Attachments: HADOOP-16085_3.2.0_001.patch
>
>
> Currently S3Guard doesn't track S3 object versions.  If a file is written in 
> S3A with S3Guard and then subsequently overwritten, there is no protection 
> against the next reader seeing the old version of the file instead of the new 
> one.
> It seems like the S3Guard metadata could track the S3 object version.  When a 
> file is created or updated, the object version could be written to the 
> S3Guard metadata.  When a file is read, the read out of S3 could be performed 
> by object version, ensuring the correct version is retrieved.
> I don't have a lot of direct experience with this yet, but this is my 
> impression from looking through the code.  My organization is looking to 
> shift some datasets stored in HDFS over to S3 and is concerned about this 
> potential issue as there are some cases in our codebase that would do an 
> overwrite.
> I imagine this idea may have been considered before but I couldn't quite 
> track down any JIRAs discussing it.  If there is one, feel free to close this 
> with a reference to it.
> Am I understanding things correctly?  Is this idea feasible?  Any feedback 
> that could be provided would be appreciated.  We may consider crafting a 
> patch.



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