[Gross] N-way cluster

[Rolf E. Sonneveld]

Eino Tuominen wrote:
> 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?
>   

didn't see any replies. So here's my feedback: it sounds to me very 
promising! One comment: the satellites should have redundancy regarding 
the master host to use: e.g. of master host 1 is not reachable or 
doesn't respond fast enough, use master host 2.

I'd suggest on a second track (in parallel) we try to make some PR for 
the gross. It is my experience that for products, that are widely used, 
it is not hard to justify the time investment needed to learn the 
product. With products that are not widely used it's often a matter of 
'install, configure a minimum set, run and hope it will keep running'. 
Getting gross used by many people will more and more justify the time to 
learn the details of the product for all mail managers.

For distributed environments I think it's a great product with many 
possibilities. I was thinking about a link on the Postfix HOWTO's page, 
for example, and probably one at the SJSMS wiki page, and I'm sure there 
are more locations to do some PR. Just my $0.02. Ehhh, € 0.02 ;-)

/rolf