Total requests per day on a VIP

There are several ways you can collect this information. If the virtual server has an HTTP profile on it (which it probably does), total HTTP requests are shown in Statistics > Module Statistics > Local Traffic. Select "Virtual Servers" from the "Statistics Type" pulldown and view the total number of HTTP requests in the Requests column. The number shown reflects the number of requests since the last time the statistics were reset, which can be done from the Config utility or from the command line (perhaps via a script).

You could also use an Analytics profile on the virtual server to collect a lot of different information about HTTP traffic through it. Here's the jump to the BIG-IP Analytics Implementation Guide for v13.0. (You can find similar doc for other BIG-IP versions.)

You could also use a simple iRule to automatically record (and periodically reset) the number of HTTP requests through a virtual server. You could use a statistics profile with STATS commands, use iStats commands, or even use the session table to record and report on the statistics. Check the iRules Wiki on DevCentral for examples, or come to one of our Developing iRules for BIG-IP courses. We cover all of these features and much, much more!