We currently have an environment with an IIS front end (our application server that provides IIS and connects to the backend SQL). It is one IIS server and we have a duplicate configuration on another server for a backup.
We are looking to add HA in several areas and I have done some research into a couple attractive options. We are planning to add another physical server and load balance in a way that when one server fails, the other is functional and IIS continues to function until we can get the other server up.
Here are the two options I am looking at:
1) Using NLB in Server 2008 to load balance both servers.
2) Hardware NLB device to perform the load balancing.
My question is, is one a better option than the other? I know the hardware NLB is more expensive, but it may be worth it by avoiding the NLB config on the two servers. Just looking for expert advice on this. Also, if hardware NLB is the better way to go, could someone recommend which devices seem to perform the best with least chance of failure?
Thanks!
In your case, I would say maintaining Server 2008 NLB would require significantly less administrative effort than adding hardware load balancers and keeping the webserver configuration in sync.
It would also keep the level of complexity down - adding hardware load balancers adds a lot of extra network complexity as well. If you don't have a network engineer who really understands layer 2 through 7 packet flows, you will struggle to make things work effectively.
If you want to learn more about hardware load balancers, F5 (http://www.f5.com) is the "gold standard". I like A10 (http://www.a10networks.com) a lot and have had good success with their products. They attempt to compete directly with the big boys like F5, but they're a pretty new company, so probably not quite as well baked technology. Kemp (http://www.kemptechnologies.com/) is another fairly new company and probably the best from a price perspective. I've had good luck with them when I needed support.
I've used all three companies products and would be willing to use any of them again. Get them competing with each other and the pricing will be much better.