Optimizing Web Content Delivery Using Web Server Accelerator

Traditional web servers generate and deliver web contents in the same context. While the generation part becomes more and more complicated due to the complexity of implementing various features, the delivery part remains relatively simple and can be efficiently processed. This asymmetry leads to difficult and challenging issues in optimizing the web server performance.In this paper, we describe the design, implementation, and performance evaluation of a web server accelerator, called Tornader. It resides in front of a web server and improves server performance by efficiently delivering cached responses while leaving the role of content generation to the web server. Due to the scalable architecture design and various optimization techniques, Tornader can boost the performance of the most widely used Apache web server up to 150% under high load condition and shows scalable performance enhancement in multiprocessor systems. Furthermore, it can be used on most modern operating systems, since it is entirely implemented as a user-level program using POSIX API.