What is Availability?
Availability refers to the ability of an organization to deliver consistent, predictable access to applications and data. As email is increasingly seen as an essential business application availability models are now being applied to messaging servers such as GMS.
Gordano provides a variety of different availability models up to and including carrier class availability. Carrier class availability is often call "Five Nine’s" to reflect the fact that the system should be available 99.999% of the time.
The cost of providing additional guaranteed reliability goes up as the required reliability increased. According to The Economist, adding a 9 increases the application cost by a factor of about 50. So if an application costs $100 for 99% reliability, expect to pay in the region of $5,000 for 99.9% and $250,000 for 99.99% availability. Clearly, any offering with an availability of 99.999% less than $12,500,000 should be viewed with skepticism.