redirect part of the traffic

So, to make sure I understand:

 

 

For every 100 requests that come in, 3 of them need to have a 302 issued in order to redirect the browser somewhere else.

 

 

One way to accomplish this is to apply a STATS profile to the virtual server, than increment the counter as needed via an iRule.

 

 

Take a look here for an example of using a STATS profile for reporting:

 

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=66

 

 

 

...here, for a look at the STATS::incr commmand

 

http://devcentral.f5.com/Wiki/default.aspx/iRules/STATS__incr.html

 

 

...and here for a rule that grabs info from the STATS data for decision making (in this case, whether or not to display a 'under maintenance' page:

 

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=70

 

 

I'm going to fire up my lab box in a little while, but I think this should be fairly straightforward, assuming I have your requirement correct.