Yep, we currently have one prod license and one test/devl license. With the critical nature of the interface engine, it’s pretty easy to justify a standalone server for test/devel. Can your organization accept the risk of an extended downtime if development works crashes or corrupts the Prod environment? Sharing the same physical box opens you up to all sorts of possibilities. We cannot accept the risk so we implemented a standalone test/devel server and license. The second server/license will also give you more flexibility and options when doing operating system or cloverleaf upgrades and testing.
