Businesses and their customers rely on applications being consistently available along with the databases that store their information. Database outages can cause enormous business problems. If there is a failure that requires us to recover a very large database, we are looking at a near disaster for the business. Db2 and z/OS work together with hardware features to minimize the need to recover our data while keeping our applications available.
It may sounds silly, but the key to high availability is to avoid outages. Avoiding those outages requires a certain amount of redundancy. Each hardware component that may fail (and that's all of them) needs to have at least one backup that can take over immediately. In some cases, you can use the redundant component together with the primary component to improve performance, as long as you remain aware that the performance will be degraded during a failure. But then, being up and slow is usually better than being down.
