Load balancing and failover clustering are both methods used to increase the availability of services to make sure that your systems stay up and running.
When considering whether a load balanced system or failover cluster is required remember that:
- With a load balanced system you will need to ensure that the data is identical across each system in the set, that there will need to be a mechanism to resolve conflict resolution or ensure conflicts cannot happen and finally there must be a way to maintain state so that the users information is not lost when moving between systems.
- With a failover cluster there is usually a single copy of the data and each service. This creates a single point of failure in the resilience and if multiple copies are required it will increase costs significantly especially if geographical disparity be required.