The Importance of the Number Nine When Talking About Reliability

By admin, Platform28 on January 31, 2014

The importance of reliability in the cloud domain cannot be understated. Solid reliability equates to your system’s availability and how many minutes or seconds of downtime is acceptable in your environment. Many factors are considered to ensure reliability consistency. Providing world-class reliability depends on well-thought-out planning and an ongoing assessment of potential risk factors.

The more number “nines” in your cloud provider’s service level agreement (SLA) is directly related to the level of system availability (read reliability). Wikipedia states, “availability is usually expressed as a percentage of uptime in a given year.” Take a quick look at this table that gives you an idea of the vast difference between a system that gives you three nines availability versus a system that guarantees you five nines.

Availability % Downtime Per Year Downtime Per Month Downtime Per Week
99.9% 8.76 hours 43.8 minutes 10.1 minutes
99.99% 52.56 minutes 4.32 minutes 1.01 minutes
99.999% 5.26 minutes 25.9 seconds 6.05 seconds

The Negative Impact of Sub-Par Reliability

In 2012, a well-publicized failure by Amazon’s cloud computing services involved significant outages caused by a large electrical storm and power failure in Northern Virginia and Washington D.C. (Source: These outages affected services to Netflix, Pinterest, Heroku, and Instagram – some pretty heavy hitters in cyberspace.

The damage to business ranges from economic turbulence, including loss of revenue and new sales, to psychological factors – loss of confidence among your customers, both current and prospective, and detriment to your image and reputation.

High profile outages such as these have certainly fueled reliability skepticism for businesses that are considering a move to the cloud. Fortunately, these cases are few and far between, and they should not cause anxiety for a company that has taken the time to research and wisely select a reliable cloud vendor.

How to Ensure Cloud Reliability

While considering a move to a cloud-based vendor, ask prospective vendors these key questions:

  • Can they provide past and current successful uptime statistics?
  • How do they ensure reliability and availability?
  • What SLAs can they offer?

In the event of unexpected and uncontrollable circumstances, an experienced and reliable cloud vendor will always have a Plan B, and a Plan C, in place. A smart cloud host will divide resources among different availability zones and separate physical data centers. Geo redundancy is an important ballast for reliability and availability in cloud computing.

According to a 2013 survey by, 75 percent of respondents have experienced improved service availability since moving to the cloud. These gains prompted an additional 43 percent to state they wished they’d moved to the cloud earlier.

There is no question that there have been stories of reliability issues in the past with some cloud vendors. Today, however, many cloud vendors have capitalized on innovation and past experience, while maintaining a steady dedication to understanding their customers’ needs in order to ensure reliability at its best.

About the Author: Alexandra Warner is the VP of Marketing at Platform28, a robust Communications-as-a-Service provider for the enterprise. Since 2001, Platform28 has been helping government agencies, enterprise and US Tier 1 carriers streamline their communications, drive business efficiency, and deliver an excellent customer experience.
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