How to explicitly select another "next active" unit for traffic-group?

Hello, guys and gals,

just recently I've upgraded some LTM systems to a 11.2 version. With its new ability to create device clusters we decided to use one spare box to create a three-way cluster in a scenario where two boxes are on a primary site and the third box is on a backup datacenter. The point is to keep the traffic on a primary site as long as possible.

Of course - this requires a controlled way of failover. Ie: First unit in a primary site (let's call it ltm1) needs to failover only to a second unit (ltm2) in a primary site. Only if both devices in a primary site are down (or the whole site is down) the third unit (ltm3) in a backup datacenter should go active.

In other words I need a failover scenario like: ltm1 -> ltm2 -> ltm3

Pretty simple.

The problem is the LTM systems decidec the better way would be ltm1 -> ltm3 (->ltm2). Ie: The "Next Active" unit for the default "traffic-group-1" is always the ltm3 no matter what I try.

The documentation about "Next active" property says "The next active device can be either system- or user-selected, and might or might not be the default device." (see here ). But though I&39;ve really searched hard I found no way to select other "next active" device or at least influence in some way the decision algorithm.

If anyone has any experience or idea in any way regarding this, please let me know.

Thank in advance

Pavel Svika.