1. Try think of using a cookies stickiness if you really need to stick a user session to one particular server until he terminates that session.
The shopping cart eaxample, the need here is he should be allowed to stick to the same server until he terminates the sesion otherwisae if he is load-balanced onto a different server in the middle of shopping, he will loose everything on his cart.
2. In a High availability environment where you employ more than 1 CSS to provide fault-tolerance, you need make sure you that 'fatal-sharing' is properly designed. If you miss this there will be assymmetry in the traffic flow. To avoid this enable critical-services, reporters and do vrid-peering, binding phy interfaces, upstream pining etc.
3. Considering the design, avoid one-armed topology rather to make life easier use routing topology. Have 2 VLANs one for client side and another for server side. Use 2 different ip subnets. Let the server segment be a non-routable private ip range there by use full-proxy config.
