Load Balancing for a Busy Site

[rogerd]

For a busy site that's straining its current front end server, we've been offered a variety of load balancing solutions, ranging from hardware load balancing to DNS rotation.

It seems like a dedicated hardware load balancer is the optimal solution; we've played with DNS load balancing and it seems to create some issues. We're looking at balancing two high-end dual Opteron servers initially, but might later have to add one or more additional servers to the mix.

Any insights? The host we are currently with wants $600/mo for the hardware load balancer, which seems pretty high to me.

[rogerd]

I've had the suggestion that done properly, round robin DNS rotation can be effective. Software load balancing has also been suggested, but I've generally heard bad things about that approach.

Anyone shed some light on those or other options?

[stajer]

You might be able to negotiate that lb fee. My host charges us $150 setup fee for a hardware load balancer plus $75 per server per month balanced. So we balance 4 web servers behind a load balancer and the fee is $300 per month.

[sja65]

IPVS (linux software load balancing) works great. I use it in front of a 20 machine http cluster and in front of a smaller application cluster. The real trick is getting the failovers set up the way you want and avoiding any single points of failure. My first web cluster I had everything set where I thought I would need multiple hardware failures before causing an outage - a gateway with a failover, extra machines in the cluster, redundant power, redundant internet connections - I forgot the ethernet switch that all the machines were plugged into.