Re: Question about high availability/load balancing

> Your point about running each machine as both a "real server" and as a
> router being a messy setup is well taken.

I've experienced running LVS-DR using both directors as real servers and it
works quite well. Just needed to modify pulse to be able to launch commands
when a director takes over.

This way, in my 4 servers setup, I have 2 directors and 4 real servers. All
the best one can wish for both HA and load balancing :)


> My question, then, is that if I have 4 independent clusters each running
> a different task, can I just get 2 more machines, and use them as the
> routers for all 4 clusters?

Sure you can. But unless you've got money to waste or very greedy
applications, you could just use 2 of the 8 servers as directors, and split
all 4 applications on the 6 remaining servers. Do you have any constraint
prohibiting running several apps on the same machine ? If not, you could run
each app on each real server, and then have the load of each app balanced to
6 servers (or even 8 if you use the directors).

> Or is it possible to set this whole thing up as one cluster, even though
> different members of the cluster are performing different tasks?

Once again, it is possible. You would have 4 VIPs, each of them matching 2
distinct real servers. But unless you do have constraints, it is less
powerful than splitting the traffic to 6 real servers.

Regards,

-- 
Sébastien Bonnet
  Centre de contacts - Experian France