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A seeming innocuous phrase that sounds as if it could be the name given to a downtown district of a sprawling metropolis or a local sports team, “Five Nines” actually refers to a desired level of system availability.
Ever since man began to create and use more complex machines and tools he has been locked in an eternal battle to keep them working and to improve their performance. But the emergence of cloud computing has freed many companies from the daily tussle between hardware, software, random events and erratic connectivity.
The idea of Five Nines is a classic case of an essentially contested concept, and the debates that whirl across the internet over its validity as a concern of modern businesses demonstrate that it cuts to the very heart of the direction that cloud services are heading in.
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But can such a contentious subject be of any use to you and your business?
What the hell is Five Nines?
Five Nines is a derivative concept that comes from the broader computer science ‘Class of Nines’ measure of system availability. In the Class of Nines, Five Nines refers to the fifth class or 99.999% system availability (where One Nine would equal 90% and Seven Nines 99.99999%).
What is meant here by the term ‘availability’ is not simply referring to how often a device breaks and gets fixed, but also how long it is out of service or unavailable for its intended use due to upgrades and maintenance.
99.999% system availability means that theoretically you will not be able to use (downtime) the device in question for 5 minutes and 26 seconds every year. In recent years, many cloud providers have begun to formalise a commitment to providing customers with Five Nine availability in their Service Level Agreements.
In a modern business environment where it is argued that losing system availability for even just an hour or two can lead to a serious loss of commercial activity, the concept has been held up as the standard which cloud providers should be able to deliver, and that therefore businesses should come to expect.
The dangers of downtime
Whatever your opinion on the validity of the Five Nines concept for cloud services availability and business, it can be hard to deny the dangers of downtime. Research shows the average medium sized company will experience around 15-20 hours of unscheduled downtime a year, during which orders can be dropped, applications and data can’t be accessed and customers may be lost.
The problem of downtime begins to become magnified if your organisation begins to have multiple sources of potential downtime resulting from a lack of central system coherence as a whole. Many businesses have hardware and software of widely differing ages and conditions and a lack of consistency between systems, storage and networking architecture. This can allow small problems to snowball until you end up with a significant amount of unscheduled downtime across your system as a whole, requiring significant time and effort to plug the many leaks.
The importance of Five Nines to your business
The reason why the dangers of downtime highlighted above can be so vicious is because they are ‘unscheduled.’ Downtime that is planned for, such as for upgrades or physical repair, is not necessarily a problem for a business as preparations can be made in advance.
But we have already seen that unscheduled downtime can happen to any company and that a whole host of factors besides system availability can contribute, so where does that leave us.
The answer is that it is not system availability but business continuity that is the important factor in this equation.
Is disaster recovery more important than high availability?
Some people and companies (like New Voice Media) have begun to argue that to focus on Five Nines is to miss the point, and that instead of trying to stop downtime altogether, we should be focusing on cloud based disaster recovery as a way of ensuring that the inevitable downtime isn’t very damaging to businesses at all. For most small and medium sized business data and back up are likely to be of far more importance then only having 5 minutes of unscheduled downtime a year. Continuity, not availability necessarily, is the thing that most businesses really desire.
The essential challenge is to try and get your business into a place where, as much as possible, you can react to challenges in a proactive and efficient way rather than in a simply reactive one.
Do you think that the concept of Five Nines is as important for businesses as some people in the cloud services industry make it out to be?