A previous Tech Tip talked about the advantages of the N+1 configuration for multinode clustering (read it). It's one reason why IT professionals choose Veritas Cluster Server for high availability solutions.
Smart failovers are the best failovers
There are other reasons for using Veritas Cluster Server—for example, smart failovers. Using the Intelligent Application Failover Policy of Veritas Cluster Server, you can configure a smaller application to fail over—not just to the standby server—but to another active server that has enough spare computing power to run it. For example, if server B has enough spare CPU cycles to run the application on server A, server A can fail over to server B—keeping D available as a failover target for larger applications.
This highly granular active/active approach uses spare capacity instead of dedicated spares, and takes server utilization and hardware savings to new levels. Veritas Cluster Server has built-in policies to account for application compatibility, affinity, dependency, prerequisites, and more to ensure that applications intelligently fail over to the "best fit" server at that moment in time.
Where's the (simulated) fire?
You've implemented a high availability solution but now you wake up in the middle of the night and wonder, "Will it work when I need it?" You could shut down production for a few hours and test it, but you'd have some unhappy people to answer to.
Veritas Cluster Server can help. Its Fire Drill feature simulates an application failover without impacting production. Fire Drill basically validates the failover, giving you a little extra peace of mind.
Also, the free, downloadable Veritas Cluster Server Simulator allows users to easily experiment with and tune their intelligent failover behavior before transferring the finished configuration to their real (not simulated) cluster.
All clustering solutions are not created equal. Make sure you consider all aspects of your high availability solution when choosing the right clustering software. After all, most people find out about the inadequacies of their high availability solution at the worst possible time—when they're trying to recover from a failure. Don't be one of them.