performance and impact of STREAM Expression

Hi Puli,

I haven't done or seen any stream specific performance testing. I've implemented it at a number of customer sites though. I wouldn't add the iRule to a unit which is already at 80 or 90%. But I'd be confident in using it on a lower unit with lower utilization.

Make sure to disable the stream filter in HTTP_REQUEST in your rule though:

when HTTP_REQUEST {
    Disable the stream filter by default on all requests
   STREAM::disable
}
when HTTP_RESPONSE {
    Check if response is text
   if {[HTTP::header value Content-Type] contains "text"}{

       Set expression to find/replace and enable the stream filter
      STREAM::expression {@http://domainA@http://domainB@}
      STREAM::enable
   }
}

If you want to get estimates before putting it into production, you could enable timing on the iRule and test it on a test virtual server or test LTM:

http://devcentral.f5.com/wiki/iRules.timing.ashx

Aaron