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https://issues.apache.org/jira/browse/LIBCLOUD-273?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mahendra M updated LIBCLOUD-273:
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    Attachment: local_hash.diff
    
> Provide hash values for local storage
> -------------------------------------
>
>                 Key: LIBCLOUD-273
>                 URL: https://issues.apache.org/jira/browse/LIBCLOUD-273
>             Project: Libcloud
>          Issue Type: Improvement
>          Components: Storage
>            Reporter: Mahendra M
>            Priority: Minor
>         Attachments: local_hash.diff
>
>
> This patch provides a 'hash' value for the stored object.
> There are two approaches possible.
> 1) For every object stored / downloaded, calculate the MD5 hash on the fly. 
> Store the cache info in a folder '.hash' - which is excluded from the content 
> listing. Use this cached value in the future. If file time-stamp changes, 
> update the cache
> 2) Just provide a MD5 hash of the stat.st_mtime of the file.
> Approach (1) will give a true hash of the object.
> Approach (2) will give an indication about changes in the object. Like an 
> ETag.
> Approach (2) is similar to how S3 storage works. The hash returned by S3 is 
> not the content digest. It is just  an ETag. So, in local storage, we can 
> take Approach (2).
> We can migrate to Approach (1) in the future, if required.

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