dovecot - Oct 2009 - Multiple postfix + single dovecot - optimal configuration

Hello,

I want to setup dovecot with two postfix servers on three machines:
- dovecot - with huge amount of disk space - where all user emails will
be kept,
- postfix1 - with greylisting, amavisd-new (spamassassin, clamav, etc),
with mysql backend,
- postfix2 - same as postfix1.
MX priority will be set to the same value for both postfix machines.

For now I don't know how to "glue" these severs:
- if I should install dovecot on both postfix and use third servers as a
NFS share?
- or maybe it is possible to communicate with dovecot on third server
via LMTP?
- or should I run third postfix daemon (without antyspam etc - simple
configuration) on the same machine as dovecot only for delivering local
mails?

I will be grateful for any advice, howto or good practices example.

-- 
Regards,
Thomas.

Tomek schrieb:
> Hello,
> 
> I want to setup dovecot with two postfix servers on three machines:
> - dovecot - with huge amount of disk space - where all user emails will
> be kept,
> - postfix1 - with greylisting, amavisd-new (spamassassin, clamav, etc),
> with mysql backend,
> - postfix2 - same as postfix1.
> MX priority will be set to the same value for both postfix machines.
> 
> For now I don't know how to "glue" these severs:
> - if I should install dovecot on both postfix and use third servers as a
> NFS share?
> - or maybe it is possible to communicate with dovecot on third server
> via LMTP?
> - or should I run third postfix daemon (without antyspam etc - simple
> configuration) on the same machine as dovecot only for delivering local
> mails?
> 
> I will be grateful for any advice, howto or good practices example.
> 
examples with Ha loadbalancing setups were discussed before on this list
look at list archives will give you starting points

-- 
Best Regards

MfG Robert Schetterer

Germany/Munich/Bavaria

Quoting Tomek <timor at o2.pl>:
> For now I don't know how to "glue" these severs:
> - if I should install dovecot on both postfix and use third servers as a
> NFS share?
This will work, but doesn't scale well and performance problems may be hard
to pinpoint.  You have to be very careful when using NFS like this, but it
is possible and fairly easy conceptually.
> - or maybe it is possible to communicate with dovecot on third server
> via LMTP?
No idea...  You could surely configure the two postfix machines to deliver
to the dovecot server via LMTP.  Very similar to your next version below
if used that way.
> - or should I run third postfix daemon (without antyspam etc - simple
> configuration) on the same machine as dovecot only for delivering local
> mails?
You could do that.  Scales better IMHO than option one...  I ran this way
for years (but don't anymore).

You could also cluster the machines and use a cluster filesystem, but that
may be outside your comfort zone.
> I will be grateful for any advice, howto or good practices example.
Depends on a lot of factors, so in the end you will have to decide...
Good luck with it.
> --
> Regards,
> Thomas.
-- 
Eric Rostetter
The Department of Physics
The University of Texas at Austin

Go Longhorns!