Three web server software products dominate the market. Apache has the largest installed base, as one might expect from software distributed free of charge. Netscape and Microsoft's Internet Information Server may become the more prevalent as they are commercially maintained and developed.

The good news for managers of web sites is that a 'common log format' has been agreed across these three web servers. These logs provide data of use to system and performance managers. The various logs and a summary of their contents are:

• Access Log - users who accessed the site, what they requested, success codes and response time.
• Agent Log - browser and operating system used per access.
• Error Log - errors recorded per transaction
• Referrer Log - the page from which each user arrived

For the performance manager the Access Log offers the most useful information. Experienced performance managers will already be salivating at the thought of the 'response time' information mentioned. One must not get carried away however. The response time figure per transaction is rounded up or down to the nearest second. For most web transactions this means it is recorded as zero! The intent is appreciated however, and it offers hope that, with user pressure, the basic recording of information will be refined in the future.

Various freeware and shareware is available to access, display and manipulate the data in these logs. Entirely at your own risk, a list of 26 such products, and the web addresses from where they can be obtained, is available on request from techinfo@metron.co.uk

Given the ready availability of such information as freeware/shareware, it ought to be in any web orientated performance product as a standard function. For supported functionality in this area, Metron always recommends using commercial software for such purposes.