On Mon, 7 Jan 2002 20:25, Andrew Newton wrote:
> Simon Cocking wrote:
> >>>Has anyone contemplated modifying Courier to support the storage of
> >>>messages in SQL tables rather than Maildirs?
> >>
> >>Why?  Give me a logical reason other than "it sounds cool."
> >
> > Two words -- replication and redundancy.  We already have systems in
> > place which make use of replicated MySQL databases for load-balancing
> > and redundancy.
>
> I'll have to admit, it does sound cool.  But I can't get much beyond
> that point.  You can replicate the mail for redundacy to another system
> or folder or whatever using a .courier file and maildrop or procmail.

Sure -- getting mail between servers is easy.

> It seems to me the ultimate goal is to replicate not just the mail, but
> the state of the mail back and forth.

*Exactly* :o)

> So your message may flow into
> server A and then get replicated to server B.  Then, the user deletes
> half of the messages in a session with server B and those messages get
> deleted from server A (hopefully before the user carries out another
> session with server A).  Does MySQL do all that for you?

Yep -- data-altering queries are executed by each server in the pool, so 
if a message is deleted on one server, it's deleted on all.  Same goes 
for status updates, too -- and it's fast.

The beauty of using SQL as a message back-end would be that you could set 
up an array of SMTP/POP/IMAP servers in a DNS round-robin arrangement, 
and users could hit any one of them at any time and it would appear to 
them to be the same server.  Need more horsepower?  Just add a new server 
to the pool.  Need better availability?  Distribute your servers over 
multiple physical sites with different bandwidth providers.  Want 
centralised stats & reporting?  It's all *already* in the database.  
Plus, user management is just an SQL query away.  All without a central 
point of failure.

> Well, to get it into the database, you could just setup a .courier file
> to pipe the mail into your sql-loading app.  The hard part would be
> getting the IMAP and POP servers to look there.  And any other
> application.  The think I like about Maildir is that mutt and other
> things also know how to read it.

My need is purely IMAP & POP3.  Command-line access to mail is not in the 
picture, although I agree that interfacing filesystem-based mail readers 
would be a challenge :o)  Having said that, at least Pine / Elm support 
IMAP anyway.

-- 
Simon Cocking <[EMAIL PROTECTED]>
Network Operations
MailGuard Pty. Ltd.
-- 
Message protected by MailGuard: e-mail anti-virus and content filtering.
http://www.mailguard.com.au



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