Things just aren't as simple as they used to be. There was a time when we could achieve nearly all of our uptime goals just by clustering our backend database servers and maybe a handful of other application servers. There was very little of that weird virtualization voodoo going on, and all our important
applications ran on physical servers.
Well, times have changed. Not only are a larger share of our applications considered mission critical, but our service level agreement expectations are much higher and we're under pressure to virtualize more applications in order to realize greater cost savings in the data center. To further complicate things, those applications have grown more complex with more moving parts. For those of us concerned with high availability and disaster recovery, this has presented some interesting challenges.
Consider, for example, an online...