De-duping attachments

Patrick Goetz pgoetz at
Wed Sep 15 17:12:37 EDT 2010

On 09/14/2010 11:55 PM, Rob Mueller wrote:
> Eg. An architectural firm
> might end up sending big blueprint documents back and forth between each
> other a lot, so they'd gain a lot from deduplication.

Not to throw a damp towel on this discussion, but isn't this really an 
administrative problem rather than a technical one?  I.e. shouldn't the 
system administrator set up a version control system or even something 
like dropbox for file sharing rather than using email for this situation?

 > if you know the same file is being sent back and forth a lot with
 > minor changes, you might want to store the most "recent" version,
 > and store binary diffs between the most recent and old versions
 > (eg xdelta). Yes accessing the older versions would be much
 > slower (have to get most recent +
 > apply N deltas), but the space savings could be huge.

My users frequently mail documents to the person in the office next door 
(never mind that both their home directories are on the same server!); 
however this content is almost always different for each attached file; 
i.e. without re-implementing a version control system under IMAP, as 
you're suggesting, there would be little benefit in keeping and hard 
linking to a single copy of each file.  However, that seems like it 
fails the UNIX "do one thing, and do it well" test pretty badly.

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