32. High Availability Technologies

A high-availability (HA) strategy helps improve the availability of the system due to hardware, software, or network malfunctions. Even though it sounds similar to a backup and disaster-recovery (DR) strategy, it is not the same. A high-availability strategy serves as the first level of defense, making a hardware failure or software crash transparent to users. Disaster recovery, on the other hand, deals with situations where a system needs to be recovered after a disaster that was not prevented by the high-availability strategy in use.