In a sense, high availability (HA) systems attempt to provide the ultimate in disaster recovery and business continuity solutions for the Information Technology market. HA systems are architected with redundancy in mind. Fast, real-time agents immediately detect changes in any system, its applications, and their underlying data, while conveniently backing up those changes on to widely distributed servers. In the event of any system failure, a seamless failover happens — essentially undetected by the users of the system.
The Quest for 100 Percent Availability
Note that high availability isn’t called perfect availability or always available. In fact, the pinnacle of many HA architectures is to achieve “Five 9s,” which stands for a 99.999 percent availability factor. Companies that invest in an HA solution for disaster recovery find that it can be the ultimate for business continuity planning.
Backups and failover processes are key technical components of any HA solution. The RAID concept for hard drive arrays illustrates the use of high availability principles applied to the data storage on a singular server. Newer network architectures like storage area networks (SAN) take the RAID idea and apply it on a larger scale.
With most SANs offering embedded backup and restore, as well as disk mirroring and data redundancy, it makes sense that this storage network architecture gets used regularly in high availability systems. Fast data retrieval is vital for HA systems to achieve the proverbial Five 9s. At the same, taking a real-time snapshot of system data also helps with overall availability — when a system failure occurs, any application data remains up to date.
Testing is Vital for All Components of an HA System
All components of an high availability system — servers (virtual or physical), storage (RAID or SAN), applications, and networking equipment — need to be thoroughly tested, both individually as part of an entire system test. This is really no different from any other information technology architecture, but when considering the goal of 99.999 percent availability, testing becomes especially paramount.
Support for Multiple Operating Systems
Commercial providers offer HA systems that support most of the major computer operating systems, including Windows, Linux, Unix, and larger scale enterprise architectures. When considering the hybrid nature of the modern IT operations shop, a state of the art high availability system needs to easily support multiple operating systems as well as the combination of on-premise and Cloud-based servers. IT Ops engineers researching HA systems for their own business need to pay close attention to specifications of any system before purchase.
Organizations looking for the pinnacle in a disaster recovery solution, need to explore high availability systems to see if the promise of seamless business continuity is worth the cost. This added redundancy of systems, applications, and data offer instantaneous failover while business operational efficiency remains unchanged.