WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

Server hardware and operating system layer
Take the time to verify that the servers used in the application environment have
been tuned adequately. This includes network options, TCP/IP settings, and even
possibly kernel parameters. Verify disk configurations and layout as well. The
tuning at this layer can be quite difficult without a specialist in the server
hardware or the operating system, but the adjustments can lead to significant
improvements in throughput.
7.3.3 Application environment tuning
Within the WebSphere Application Server environment, there are many settings
that can increase application capacity and reduce performance issues. The
purpose of this section is not to directly discuss those tuning parameters. This
section, however, should generate some thoughts on what settings to consider
when designing a WebSphere Application Server environment.
Web server
The Web server with the WebSphere plug-in should be tuned carefully. There are
many different configuration options that impact the performance such as
keep-alive settings, number of concurrent requests and, so on. The number of
concurrent requests is perhaps the most critical factor. The Web server must
allow for sufficient concurrent requests to make full use of the application server
infrastructure, but should also act as a filter and keep users waiting in the
network and avoid a flooding of the applications servers if more requests as the
system can handle are coming in.
As a rough initial start value for testing the maximum concurrent threads can be
set as follows:
MaxClients = (((TH + MC) * WAS) * 1.2 1 ) / WEB
Where:
– TH: Number of threads in the Web container
– MC: MaxConnections setting in the plugin-cfg.xml
– WAS: Number of WebSphere Application Server servers
– WEB: Number of Web servers
DMZ secure proxy server
The DMZ secure proxy server is designed as a possible replacement of the Web
server with the plug-in. The same tuning considerations apply for the DMZ
secure proxy as they do for the Web server with the plug-in loaded.
1 This allows 20% ot the threads to serve static content from the Web server
Chapter 7. Performance, scalability, and high availability 237