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JS - it depends on what your portal is used for - ours has registration (which is heavily used), 4 weeks of the year you are at maximum capacity. Basically, our portal is a stepping stone, load is manageable year round, however during registration additional servers added. Are you measuring the performance of the portal or the system integrated with the portal? 2 stage approach, channels load scripts, Perl http web test, HTML unit (java framework) - traverse menu trees - test portlet load. Problem with this approach is that when you add a new channel the script will have to revised. Average 40-53K unique visits, 1.8M page views.
ED - many people miss the total number of unique user logins, e.g. DB issues uncovered as you hit a certain number of unique users. SQL query failed. Number of rows in a DB table - portlet entity table (user layout preferences), 1 row per user per portlet. So a user would have approximately 70-100 rows, depending on the number portlets. Poorly designed SQL running against a 5-6M user base caused a failure. Need to know the total number of users that have been through the system.
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