[Gross] N-way cluster

[Eino Tuominen]

Hi,

I've received a lot of queries about supporting more that two node 
grossd clusters. Especially to Postfix admins this seems to be rather 
important issue.

Anyway, I thought of telling you what we've been planning to do. Instead 
of replicating the database to more than two hosts, we plan to introduce 
a "satellite" or "slave" mode. There would still be a two node cluster 
that would take care of the bloom filters and replicate the database 
between those two. Master hosts could serve MTA's running checks 
normally or just take care of keeping the state information.

A satellite grossd would do the tests normally, but instead of having 
the filters locally it would query from and send updates to the master 
hosts. Satellites would fetch most of the configuration (checks, weights 
etc.) from the masters, too. That would give you virtually unlimited 
scalability, and "n-node clusters".

First we have to rewrite parts of the configuration code to support 
updating configuration on the fly. So, don't hold your breath...

Feedback?

-- 
   Eino Tuominen