Hello all folks around FB there!

We are using Firebird in several projects related to accounting of
energetics equipment, work planning etc. Currently i have about 100
users online at the same time, but they are growing.
i want to make highly available database system with 3 or more
database servers involved. Whether it has to be clustering or it would
be mirroring with master/slave relationships i don't know yet.
So i'm looking for help how it can be done with FB.
The other thing i want is load balancing
between different servers.
Do you have any suggestions of how to implement this?
Thanks a lot in advance.
Eugene.