Milter-greylist

--- In milter-greylist@yahoogroups.com, Eduardo Casarero
> wrote:
> > I would prefer to have a "dummy greylist daemon" with something like
> this http://www.ispras.ru/~knizhnik/fastdb/readme.htm as DB. All the
> 20 greylists have this dummy greylist configured as peer (only 1) and
> they send to this dummy peer all the transaccions. As the transactions
> gets into the dummy, it's replyes to the other 19 clients.
>
> This is a good idea, and will help milter-greylist to handle larger
> server clusters. The dummy daemon basically acts as a home-grown DB
> server. There are two problems with it, though:
>
> 1. There is a limit to the scalability. Increasing the number of mail
> servers, the load on the dummy greylist daemon will eventually become
> too high and the setup will break
>
> 2. There is a reliability issue. If the dummy daemon fails,
> greylisting on the whole server cluster fails. It breaks the
> redundancy inherent to multiple mx servers for a single domain.
>
> Have a look at http://en.wikipedia.org/wiki/MySQL_Cluster. These
> database guys know how to do high availability and performance
> clustering. Why not take advantage of that?
>

I think that involving DB's Clusters change the spirit of milter-greylisting (its a milter) also you need DBA skills to manage such a cluster.

If you want you can have N dummy daemons so there is redundancy. having 2 dummies talking to 20 greylisting daemons has to be enough redundancy. Using mysql involves high speed disks, using a lite daemon with a couple of gb of ram should be enough (and dumping to SATA disks). Mysql is slow for thousands of smtp transactions. (of course its not slow on a biiiig installation of mysql with caches and all the flavour but it's not cheap) Imagine a DDoS...

And for the 2nd point, if dummy daemon fails greytlisting daemons should work standalone with it local DB like their work know if a peer go down.

I just think that the cost of implementing a big database such as mysql is a waste of resources and time for something so simple as milter-greylist.

>