I'm not sure we're talking of the same things.
By clustering, i mean avoiding single point of failure (so a single point of bottleneck) with HA added values in terms of availability and scalability by supporting multi servers and not one master and one slave server.
I didn't see any cluster related subject on the demo
- Apparently, the ISPConfig 3 manual
has a section on "Installing A Web, Email And MySQL Database Cluster On Debian 6.0 With ISPConfig 3"
- in the meantime, we have a Howtoforge available "Installing A Web, Email And MySQL Database Cluster (Mirror) On Debian 5.0 With ISPConfig 3
" but i don't know if the limitation in the MySQL cluster setup (locking issues) has been resolved in the updated official guide or even if Mysql has been replaced by Mariadb as we often see in various projects these days.
I also didn't see something related to load balancing except this guide "Setting Up A High-Availability Load Balancer (With Failover and Session Support) With HAProxy/Heartbeat On Debian Etch
" but i would suggest something more straightforward done by ISPConfig itself.
LVS and HAProxy
comes to mind even more. I would suggest a frontend to support such a solution. A good example and live demo of a front end for HA-Proxy => Link
. A simplier load balancer management demo but yet useful => link
The main purpose of the suggestion is ISPConfig brings a whole solution through a graphic installation / maintenance wizard in order several servers act as one.
So we would have something like one ISPConfig machine acting as the Cluster Manager (Master), and the other machines are set as Nodes (Slaves).
If any node in the cluster goes down, customers won’t notice anything except for a slight drop in response time, depending on our traffic volume. The cluster manager would display the servers up and down for whatever the reason.
The benefit here would be to rely on the added values of a control panel instead of doing everything with configuration lines (which is out of the control panel scope as, by definition, configuration lines represent the responsability work of a user).