Milter-greylist

--- In milter-greylist@yahoogroups.com, Kai Schaetzl <maillists@...>
wrote:

> 
> There is no such thing as a "single domain mx server". I assume you
mean a 
> server cluster that handles mail for one company? And further assume
that 
> a single company has only a small number of domains to handle mail for?
> Why do you think that needs less ressources than a "multi-domain"
(dozens 
> or hundreds of domains) server?

With "single domain mx servers" I mean a pool, cluster or farm of mx
servers that all serve the same domain name.

This is the worst-case scenario for greylisting, since consequent
attempts to deliver can be made to any machine in the mx pool.
Therefore, all mx servers need to be aware of previous attempts to
deliver to any of the other machines.

And how do you know that a single MySQL 
> server will handle this without throttling the processing rate on the 
> multiple mail servers?

I don't. But if not, there is a scaling solution (db cluster), while
with the current setup there is not.

> 
> I'm not saying that you are wrong. I and others just caution that there 
> *might* be problems performancewise which in the end might greatly
reduce 
> the deployment figures of such a solution. So much that it may be not 
> worth it to add such an API.

As I said, if no one is interested (and that certainly seems to be the
case), I will rest my case. So far, I have not heard a good
alternative to extend greylisting to single domains with (extremely)
large volumes. The question may be largely academic, but I feel it can
be an important vector for future development of milter-greylist.

> 
> If that is not enough, the next step up
> > will be a high performance, high availability database cluster.
> 
> You can do that. But think about that. What do you gain with this? I
think 
> you gain very little but invest a lot of hardware and personell 
> ressources. I think most vendors are unlikely going to do that.

Well maybe. But remember these are large scale operations to begin
with (domains with 50 mx servers or more), so adding a database server
is not unthinkable.