What is N+1 Redundancy?

When deciding on a company to host your website, it is a good idea to make yourself familiar with the provider’s data center. After all, this is where the magic happens, the facility that stores your critical data. There are many features you need to keep in mind and one of the most important is the power supply. Why? It’s simple when you think about it. Depending on the nature of your business, even a few minutes of disruption can prove to be very costly, if not disastrous. It doesn’t matter how reliable the host thinks their infrastructure is, without power, the whole operation goes down. The best remedy for this probability is a data center equipped with N+ 1 redundancy power.

How it Works

N+1 redundancy is achieved through a relatively new power sharing technology. This simply means that all the modules in the power scheme run in parallel fashion and evenly share the load. The redundancy part means that one additional module is being run to support the load, thus allowing each load to support one another. So, even if one module fails, another is there in its place to pick up the load. Because a reliable power supply is a crucial part of business survival, this type of structure is ideal for any operation where a power failure just cannot be tolerated. The utilization of N+1 power is the most efficient and cost effective way to achieve the high level of reliability required in today’s business environment.

N+1 Power in Action

A good example of an N+1 redundant power system would be three 1-A power sources connected in parallel to 2-A supply load. If the sharing technology is not implemented, the voltage source’s nature is to dictate that the power source with the highest voltage supply all of the current load until reaching its limit. From there, it becomes a stabilizer, so its voltages drop down the level of the next highest supply, which then assumes the role of voltage stabilizer and so forth. The last unit has the smallest voltage setting and winds up controlling the voltage all while providing the least current.

The major disadvantage to the method above is that all the power supplies will not be loaded equally, ultimately leading to the increased probability of failures. As each unit endures its current limit and passes voltage control onto the next, the ability to recover in the event of a power module failure becomes increasingly difficult. N+1 redundancy improves reliability and recovery time by enabling all units to equally share the load.

Who Uses N+1 Redundancy?

Today, N+1 redundancy is used in many applications. Some of its most common uses include implementation with disk arrays, processor power supplies and the actual processors themselves. It wasn’t until recently that N+1 was able to provide server-level power protection. As the demand for critical business applications and databases increase, companies like FatCow have turned to this technology to effectively power their hosting operations.

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