Crescendo's Web Application Performance Blog

In a recent webcast I talked about Crescendo’s Application Delivery Controllers (ADCs) and explained their usefulness in front-ending a web server farm. I started the conversation with an explanation about ADCs and how they load balance traffic but also help you offload heavy performance tasks from the servers. To illustrate this I showed a graph we did measuring server performance under traffic load.

 The graph shows a server handling traffic load created by an Avalanche traffic generator. Traffic rises to 6000 transactions per second (TPS) which the server handles very well. Once traffic rises above 6000 TPS, by a few 100 TPS, the results are catastrophic. The server drops traffic and response time shoots up dramatically.

Up to this point, this explanation is a numbers story. The story is about the threshold the server fails at. This seems like another technical explanation that skirts around the real issue but does not get to the heart of the matter. On a logical level it makes sense, but … so what?

Let’s look at it from another much more interesting perspective. Looking at the same issue from the business side, we can translate dropped connections to business lost - or very likely lost. The very large response times for the customers who do get service translates to frustrated customers and will very likely cause some of them to leave.

 

Looking at it from this perspective, the problem is very intuitive and one that every business must avoid. This is where a good ADC comes into the picture. On top of offloading work from the server and increasing its capacity, Crescendo’s ADC can automatically meter connections to the server and prevent flooding it. The result is that customers get predictable service at all times. The extra capacity the servers can handle with AppBeat DC will also help in cases of large crowd events like a big sale or promotion. In these cases, Crescendo’s ADC can be the conductor orchestrating all the servers to “sing”.

Take a look at the number of connections the same server can support when front ended with Crescendo’s AppBeat DC. The same server can now support 3 times the transactions. What this means is that when your next big sale comes around you can expect your cash registers to keep ringing.

 

Want to learn more about Crescendo’s AppBeat DC? Check out our video Intro to AppBeat DC.