What load-balancing system do you use in production? What do you think of it?

Question

There are a lot of different systems for balancing load and achieving redundancy in production servers (Not just web servers)

• Round-robin DNS
• Linux Virtual Server
• Cisco Local Director
• F5 BigIP
• Windows NLB
• etc?

If you use one of these (or another) in production, which one? How well does it work for you? Have you evaluated others?

Answer 1

HAProxy is an excellent software load-balancer; easy to configure, highly customisable and extremely performant (it can saturate a 10Gb NIC).

The main features which make HAProxy so suited to us:

• Easily define different traffic types, and route to the right server pool
• Extreme reliability: I've not had it crash in 9 months and counting
• Low resource usage: barely registers on CPU, and all the (small) I/O load is from logging
• Highly flexible: various balancing, session stickiness and failover algorithms

The only thing that is annoying about HAProxy is the configuration file. There is no convenient way to programmatically change a server's config, and there's a learning curve to understanding the various options.

Answer 2

For our apache processes we use(d): http://www.f5.com/products/big-ip/ This seems like the industry standard. I guess it all comes down to how much you're paying, and what you're load balancing.

e.g. Websphere could be done:

big ip -> Apache 1 -> WebSphere 1

big ip -> Apache 2 -> WebSphere 2

or you could cross it:

big ip -> Apache 1 -> WebSphere 1 & 2 (round robin)

big ip -> Apache 2 -> WebSphere 2 & 1 (round robin)

We used the latter and it worked perfectly. Watch out for the scenario where one host fails: in most cases you're going to lose that request if it just times out.

Answer 3

I've used LVS and find it very low maintenance once setup. On a side project I tried haproxy for a site where I was just balancing 3 webservers. Worked like a charm and was very easy to configure - highly recommended.