Load Balancing Based on Custom Weights

Woah, quite many questions there.

For the balancing based on JSON data, I'm pretty sure only an iRule will do. You will need to collect the request payload using HTTP::collect function because JSON data is not exposed in a header. It will be quite a complicated solution, but it's doable. Only keep in mind that to manage such complex implementations, your company will always require an advanced engineer with sufficient experience in iRules (very difficult to find). A traditional IP routing expert (even if 4x CCIE) will not be good enough. The main thing to ask yourself is if the gains are really worth it. Perhaps a standard balancing based on load observation (Observed Method) is a viable and non-complex alternative.

In regards to appliance recommendation, I'm not qualified to give the best answer, but considering the numbers seen, I figure that 5250v is the maximum you should consider going for at this point. It gives you a plenty of capacity for future scaling (more than 10x the current needs). 7000 Series doesn't have much added value, and 10000 series is a clear overkill. 5250v Is also one of my favorite bargains (hardware power to USD ratio). It has vCMP support which gives you the flexibility to build smaller isolated virtual appliances inside the same hardware for QA and testing environments.

Hannes,