1. Lect5.ppt - 02/23/06 CIS 4100 Systems Performance and Evaluation Lecture 6 by Zornitza Genova Prodanoff

2. ZGP002 Lecture Outline CHAPTER 4 - Performance Issues of Web Services From Boxes to Services - Web Server Overview Perception of Performance Where Are the Delays? Web Infrastructure Server Architectures Networks

3. ZGP003 Performance Issues of Web Services Server Architectures Web Server: An HTTP server (or HTTP daemon) - SW programs that control the flow of incoming and outgoing data on a computer connected to an intranet or to the Internet. listens for HTTP requests coming from clients over the network establishes the requested connection between itself and the client sends the requested file, and returns to its listening mode HTTP servers handle more than one request at a time.

4. ZGP004 Performance Issues of Web Services Server Architectures Web Server Problems of CGI scripts use FastCGI scripts (see Fig. 4.9b) - persistent processes that communicate with the Web server either through TCP or local interprocess communication

5. ZGP005 Performance Issues of Web Services Server Architectures Web Server FastCGIs provide isolation and persistency better performance than CGI scripts

6. ZGP006 Performance Issues of Web Services Server Architectures Web Server As shown in Fig. 4.9b, the FastCGI script is present throughout the entire life of one or more requests. The communication between the Web server and FastCGI scripts usually involves system calls. Fig. 4.9b

7. ZGP007 Performance Issues of Web Services Server Architectures Web Server The third approach, shown in Fig. 4.9c, is of applications that run within the context of the Web server. The application is invoked through APIs provided by the Web server software. Examples include ISAPI for Microsoft's IISTM Web server and NSAPI for Netscape's Web server.

8. ZGP008 Performance Issues of Web Services Server Architectures Web Server Fig. 4.9c

9. ZGP009 Performance Issues of Web Services Server Architectures Web Server The last approach is the use of server-side scripting. The page, retrieved from the document tree, contains HTML code and a script written in a scripting language. Microsoft's Active Server Pages (ASP )TM allow the use of Javascript and VBscript with ActiveX controls in a page and Netscape's Livewire allow the use of server-side Javascript.

10. ZGP0010 Performance Issues of Web Services Server Architectures Web Server A script interpreter at the Web server interprets the script and dynamically generates an HTML page that is returned to the browser (see Fig. 4.10).

11. ZGP0011 Server Architectures: Application Server Transaction and Database Server Streaming Server Multi-Tier Architecture Dynamic Load Balancing Performance Issues of Web Services

12. ZGP0012 Networks Bandwidth and Latency Traffic Special Features Performance Issues of Web Services

13. ZGP0013 Networks Bandwidth and Latency Traffic Special Features Performance Issues of Web Services

14. ZGP0014 Networks Bandwidth and Latency Traffic Special Features Performance Issues of Web Services