... give us some more configuration info please.
Like:
- are there three machines, one for the webserver, one for each MySQL server ?
- What is the task of each server ? Is one of the servers also a heavily used usenet server as well ?
- where are they located, all in the same room, or one in Tokyo, one in New York and one in Paris ?
- Did you try to look at the network performance between the servers, and if there are any, are the routers/switches configured correctly ?
- What is your defenition of slow and for what task to be performed by the website ? When you're trying to find all the members who's last name have an odd number of D's in it and have posted a message between januari 1st and februari 2nd on an evening when it was raining at least some where in Texas ... that might slow things up when we're talking say 17.000.000 members ...
Just to give you an idea what might be an issue ... don't start blaming the DB servers right away, that's too easy and only seldom the case ...
Gr,
Yveau