Re: relay outage - bounce or deffered queue

[Zalezny Niezalezny]

Ok Thanks.

On Wed, Aug 31, 2016 at 3:32 PM, Wietse Venema  wrote:

> Zalezny Niezalezny:
> > Dear Colleagues,
> >
> > in our infrastructure we are using Postfix as a relay server which is
> > responsible for transfering messages from our MS Exchange and Production
> > systems. Our infrastructure include several Postfix relays:
> >
> > M$Exchange(lan) ---> Postfix1(middleware lan) ---> Postfix2(application
> > lan) ---> Postfix3(web lan) ---> Internet
> >
> > I would like to ask You, what will happend if Postfix2 will be offline ?
> > How Postfix1 will behave ?
>
> As required by SMTP mail standard, Postfix will retry the email up
> to some time limit (with Postfix, maximal_queue_lifetime, default 7d).
>
> > M$ Exchange sending every minute ~10 000 E-mails.
>
> I recommend implementing Postfix2 etc. with multiple MTAs, perhaps
> behind HaProxy load balancers.
>
> > *If outage will take longer, we need to store thousands of E-mails in the
> > deffered queue, is there any limit for number of messages stored in the
> > deffered queue ?*
>
> Your math is off. With 1 messages per minute, that is over a
> million email messages queued for every two hours of downtime. You
> simply cannot afford days of downtime with such a volume.
>
> Wietse
>

Re: relay outage - bounce or deffered queue

[Wietse Venema]

Zalezny Niezalezny:
> Dear Colleagues,
> 
> in our infrastructure we are using Postfix as a relay server which is
> responsible for transfering messages from our MS Exchange and Production
> systems. Our infrastructure include several Postfix relays:
> 
> M$Exchange(lan) ---> Postfix1(middleware lan) ---> Postfix2(application
> lan) ---> Postfix3(web lan) ---> Internet
> 
> I would like to ask You, what will happend if Postfix2 will be offline ?
> How Postfix1 will behave ?

As required by SMTP mail standard, Postfix will retry the email up
to some time limit (with Postfix, maximal_queue_lifetime, default 7d).

> M$ Exchange sending every minute ~10 000 E-mails.

I recommend implementing Postfix2 etc. with multiple MTAs, perhaps
behind HaProxy load balancers.

> *If outage will take longer, we need to store thousands of E-mails in the
> deffered queue, is there any limit for number of messages stored in the
> deffered queue ?*

Your math is off. With 1 messages per minute, that is over a
million email messages queued for every two hours of downtime. You
simply cannot afford days of downtime with such a volume.

Wietse

relay outage - bounce or deffered queue

[Zalezny Niezalezny]

Dear Colleagues,

in our infrastructure we are using Postfix as a relay server which is
responsible for transfering messages from our MS Exchange and Production
systems. Our infrastructure include several Postfix relays:

M$Exchange(lan) ---> Postfix1(middleware lan) ---> Postfix2(application
lan) ---> Postfix3(web lan) ---> Internet

I would like to ask You, what will happend if Postfix2 will be offline ?
How Postfix1 will behave ?

a) will it bounce all messages from M$ Exchange users with answer that host
is not able to deliver messages ?

b) or maybe it will store all messages in the deffared queue for the
certain amount of time and will try to resent them every 300s ?

In case of any outage of Postfix2 or 3 I would like to store all E-mails in
the deffered queue till moment when Postfix2/3 will be again available ? M$
Exchange sending every minute ~10 000 E-mails.

How to configure it properly then ?

Using this parameter ?

*bounce_queue_lifetime*



*If outage will take longer, we need to store thousands of E-mails in the
deffered queue, is there any limit for number of messages stored in the
deffered queue ?*



*Thanks in advance for any hints*


*Cheers*

*Zalezny*