Nothing is more important than being highly available. If you don’t have operational continuity, you risk lost/corrupted data, lower productivity, lost sales and dissatisfied customers.
One of the most important things to recognize in high-availability is that there will always be something that will take you offline. Anything from power spikes to hardware failure to human error and everything in between could take your system down. It’s important to plan ahead of time to react quickly should something go wrong. There should be a procedure and system in place to minimize time to recovery should you do go down. (Many high-availability solutions rely on components that can survive a failure but not necessarily recover.) The best high availability systems have thought of just about everything but can’t predict everything. It simply isn’t possible to account for every possible thing that could take you offline.
Even “average” high-availability systems delivering 99.9% uptime, could still result in over 8 hours and 45 minutes of downtime per year! The target should be minimal or no downtime such as when 99.9999% or greater uptime is achieved. It’s easy to see that not all high-availability systems are created equal, and unless you’re pretty familiar with high-availability system design, you might have a hard time determining just how unequal they are. Fortunately, all users’ needs for high-availability are created equal – maximize uptime. So that makes the choice much simpler – much like the system itself should be.
If something is important enough to make highly available, it is important to do it right. And it is important to make right purchase decision. That way you’ll be better equipped to get the right system for your organization that will deliver the highest uptime and lowest total cost of ownership.