[Kolab-devel] Kolab2 Distribution lists using alias_maps instead of virtual_maps

[Stephan Buys]

Another issue:

kolabfilter_destination_recipient_limit = 1

in main.cf.template basically expands _any_ multi-recipient message that Kolab2 
recieves into seperate emails for each recipient.

What does this mean?

If user A sends a mail to user B, C and D.

Postfix will hit the filter/amavis/etc 3 times, once for each message. 
*It will then deliver messages to Cyrus 3 times, bye-bye single instance storage - 
trippling the amount of space used by the email on the server.

Scenario2:

User A sends an email to _external_ users B, C and D at the same external mail 
server.
**Instead of sending a message once to multiple recipients (SMTP supports this)
it will use 3 times the amount of bandwidth as a copy of the message is sent to
the external server separately. Even if using a smart/relay host.

For reference:

* Cyrus supports "single-instance" storage. What does this mean? When a message
is received for more than one recipient on the same store using LMTP Cyrus will 
save the message to disk once then hard-link the file to the other user 
mailboxes. 

** Using SMTP through telnet:
#telnet 127.0.0.1 25
220 ESMTP Postfix
mail from: <test at mydomain.invalid>
250 Ok
rcpt to: <one at myotherdomain.invalid>
250 Ok
rcpt to: <two at myotherdomain.invalid>
250 Ok
rcpt to: <three at myotherdomain.invalid>
250 Ok
data
354 End data with <CR><LF>.<CR><LF>
.

Postfix then sorts out which messages to expand or which ones to deliver 
locally. Smart-host performance is also badly affected by the current setting.





On Tuesday 29 March 2005 16:36, Bernhard Reiter wrote:
> HI Stefphan,
> those are questions for Steffen. :-)
> 
> 
> On Tuesday 29 March 2005 14:16, Stephan Buys wrote:
> > Should the Kolab2 server not rather use postfix virtual_maps for
> > distribution list expansion instead of alias_maps. IIRC alias_maps are used
> > only during local delivery which implies that recipients on non-local
> > homeservers will not get the messages delivered to it.
> >
> > Virtual maps will expand the distribution list on the server and then send
> > it out to other homeservers as well as trigger local delivery for the
> > relevant boxes.
> >
> > Also, the ldap searchstring of (|(cn=%u)(cn=%s)) makes a lot more sense
> > in main.cf.template?
> >
> > Also, has anyone noticed my issue
> 
> Which one in particular?
> 

-- 
Stephan  Buys
Code Fusion cc.
Tel: +27 11 673 0411
Mobile: +27 83 294 1876
Email: s.buys at codefusion.co.za

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