Here at Mt.Sinai, we have a separate box for our developement, and qual regions. We are in the process of upgrading our production environment to 5.3, on two new servers. The current production servers will become our test and qual regions, with HACMP running. We have always done this here for several reasons. We use the devl region (with multiple sites) to develop and test new and upgraded interfaces. Our Qual region mimics production, and this is the region we test our code for end user sign off prior to production move. We have several systems that also have 3 regions and the philosophy is the same for them. There are many reasons for our set up, we can test HA upgrades with out affecting production, run all testing with out taking the chance of any interferance to our production environments. I hope this helps. 🙂