Maintaining availability for applications can have a broad and significant effect on business processes. In general, making sure that systems are “available” through consistent server, platform and interface operation supports all of the great things that the digital age does for businesses in every industry.
Some major aspects of ensuring availability for applications have to do with measuring that availability and knowing what to measure. For instance, in figuring out availability overall, analysts might use a combination of mean time between failures (how soon something might fail) and mean time to recovery (how fast something might come back online). Metrics like these help to pinpoint the uptime of a system for understanding how available applications will be in real time.
IT professionals also have to measure availability according to user relevance. In other words, it makes sense to ask: What will be available? The only items that matter for availability are those that facilitate some end user transaction. With that in mind, it also makes sense to measure availability at the endpoints of a system, rather than somewhere else. Systems can then use an ACID or BASE model to resolve and update data across the architecture.
Along with measurements and analysis, there are core implementation strategies to create and maintain availability. The first is to create redundant systems that ensure consistent uptime, even if there is a failure at a given point. For example, Amazon Web Services, as a dominant SaaS provider, offers clients “availability zones” that implement this redundancy for high availability. Other companies may choose to set up systems like this in-house, especially if they operate multiple offices in different geographic zones.
Another core strategy is to accommodate efficient crossover – that is, to make sure that in a single failure, the redundancy process happens as quickly as possible. This combination of efforts shrinks any downtime significantly and aids in overall availability across a system.
System administrators can also pursue proactive means of limiting failures. This involves general high-level analysis of the system and pinpointing where and how failures may occur. Generally, a good redundancy system is the best protection against downtime and driver of high availability.