BigIP is deep and has lots of features that can boggle the mind from time to time. As a former customer of F5 there are a few key features that we took advantage of to make life easier for us.

One of these features is Source Address Persistence. When testing a new version of our software we would often install the upgrade on a portion of the production servers. Those newly updated servers would be defined in a network pool.  We would take advantage of the BigIP Servers and use source address persistence to route all our internal users though the newly upgraded servers. We ‘tested in production’ before taking the upgrade live to our general customer base.  This looked like:

Internal corporate network -> external gateway to the Internet (IP -> BigIP -> Virtual Server directed at test pool ( with profile that persisted all users from to the virtual server at

We would often run this for several days to make sure we had caught any issues during the upgrade. The nice thing about session persistence was that we were sure that we were 'stuck' to the test servers while testing and had not been balanced over to production boxes in our multi-tiered environment. Once we were comfortable with things, we often took advantage of the dynamic ratio feature to start to move a portion of ‘real world’ traffic to the site. More on that in another post.