Re: [exim] Sharing store

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Author: W B Hacker
Date:  
To: exim users
Subject: Re: [exim] Sharing store
jm.rodriguez@??? wrote:
> Hi,
>
> Is there any way to store a one-time email and share it with symbolic links
> between multiple mailboxes?
>
> The idea is to avoid storing the same email several times in the file system
> when the message size is large.
>
> Thank you very much.
>
>
>


AFAIK, that isn't part of Exim's stock repertoire.

Some fs have comparable inherent de-duplication features. May or may not
make good storage options for the mailstore

There are also external tools that can be run against an ordinary
mailstore, replacing physical dups with hardlinks. HOWEVER - these may
run out of the OS' link 'budget' on large mailstore.
Liewise compresson may not help.

Most large attachments (graphics files, etc ) cannot effectively be
further compressed.

There also are (or were) other MTA that managed de-duplication within a
DB. - DBMail and PowerMail. One stored the message IN the DB, the other
only header-info, indices, fs locations with the data still left in the
fs. Think of thses as an SQL-managed equivalent of hardlinks, hnce no
practical upper bound on count.

Significant space CAN be saved...

CAVEAT: Even so, ..... not necessarily recommended.

Moving really large messages can time-out an smtp session's closing '250
OK' handshake, even though 100% of the DATA has been successfuly
conveyed. This triggers *many* - resent multiple copies if the link is
less than stellar or either MTA has gone walkabout with other business.

Exactly the opposite of what you need.

BTDTGTTS

Ergo, if the message sizes are so large as to be chronically
problematic, a webalized file store, or a CMS or the like may be better
suited than smtp.

HTH,

Bill