Data Consolidation and Performance – Why Networks Fail (to Perform)

Part 4 in a series adapted from Joel Trammell’s Keynote Speech at NetQoS Symposium 2008
Is anyone out there contemplating a data center consolidation project or happen to be in the middle of one? How are you going to ensure that performance is consistent, when what you’ve effectively done– and most executives in IT don’t think about this–is move the users further away? From a networking sense that’s what you’re doing in a data center consolidation. So the ability to deliver consistent and acceptable application performance is going to be very important.
So, do you know what applications are affected? Do you know what applications are even in each of your data centers? Do you have a current baseline of performance? Do you know the traffic volumes that those applications take up so that you can properly size the infrastructure? If you have fifty Exchange servers and you’re consolidating down to three locations, can you figure out what traffic is going to go to those three locations in order to properly size those links and size those servers? Do you understand the interdependencies of all the applications?
With multi tier applications it’s not uncommon to think you’re moving the entire application when in reality you find out some of the servers just got left behind thousands of miles away. We’ve have numerous examples of analyzing multi tier applications for people where one of the tiers just didn’t get moved or didn’t get located in the same physical data center and therefore is now a thousand miles away and so then they wonder why response time and performance suddenly slowed to a crawl.
So again, response time is the key network performance driver. Traffic flows are very important for understanding capacity issues and understanding how much traffic is generated by these consolidations. Device statistics now become important as well within the data center. Am I overloading routers that have been updated as part of the data center consolidation efforts? Finally, packet analysis should be employed to understand the affects consolidation has on multi tier applications and where the servers are physically located.