Fault Tolerance Primer

Fault Tolerance is the science of determining the percentage of time that a piece of equipment will be available and usable.  In simpler terms, how often will it go down?   There are nearly as many definitions as there are engineers, but the following four are generally accepted:

Fault Tolerant: 99.99% - 100% available and able to function in spite of multiple faults, this type of solution is typically very expensive.

High Availability: 99% - 99.5% available or better, is generally affordable and a good balance of price and performance.  Many of today's proprietary telecommunications solutions fall into this category.

Fault Resilient: Newer term, implies availability of 99.9% or better.   Is affordable, and is usually based on industrial PC platforms

Standard Tolerance: 98% - 99% available, today's consumer PC's fall into this category.  The reliability can be increased through the use "redundant" or doubling up of computer parts that typically fail, such as power supplies and hard disk drives.

So what is 1% of downtime worth?  There are approximately 8,760 hours in one year.   One percent of that is 90 hours.  When you look at how important your information systems are to your business today, it is easy to see why every business owner should take this into consideration while purchasing their servers and networking hardware.  To find out which solution is right for you, try out our Downtime Calculator.