User Capacity Chart
For any given site it is difficult to predict when they will hit the limit, but if I were a website administrator, I'd be testing and upgrading my servers now.”
Durham, NC (PRWEB) November 20, 2009
Web developers are very excited. Performance improvements in the newer generation browsers enable them to open more simultaneous connections to web servers. After attending the Velocity conference and seeing the developers’ enthusiasm, Web Performance, Inc. (WPI) engineer Chris Merrill wondered what effect the improved browser performance would have on servers. The Apache Web server, like many others, has a relatively low limit on the number of simultaneous connections it will accept. Mr. Merrill and WPI decided to test the Apache server and see how it performed against the new generation browsers, specifically Internet Explorer 8.0 and Firefox 3.5. WPI’s goal was to give website administrators a rule of thumb to help them decide how soon they need to address the disparity between browser performance and server capacity.
WPI’s test explored the impact on user capacity of an Apache web server under load when the number of connections used by the browser increased from two to six. The test case consisted of a user browsing 10 pages of a typical static web site over a two minute period. The 10 pages included 141 URLs as well as two relatively large pages. The total size of the test case was just under 2MB.
The test results were surprising, not so much in what they showed, but the degree to which they showed it. Measured by performance goals under load, the capacity of an Apache web server was reduced by 60% when visited exclusively by the latest generation of browsers. With the upgraded browser performance using six connections instead of two, default connection limits were exceeded at much lower user levels.
Fixing this problem will be as easy in some cases as changing a file to configure the web server to accept a larger number of connections. However, some servers, such
as the Apache server that was tested, have a compiled-in limitation on the number of connections they will accept. In these cases, the administrators will need to re-compile Apache and load-test it before deployment.
The amount of time before this disparity starts showing up in decreased browser speed and sporadic outages depends on how close the particular server is to its capacity limits and how quickly people adopt the new browsers. As Christopher Merrill says, “For any given site it is difficult to predict when they will hit the limit, but if I were a website administrator, I'd be testing and upgrading my servers now.”
Read Load Testing Apache with IE8 and Firefox 3.5.
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