best performance alternative using multiple virtual server to bound IP/port

Hello Dear, I need to decide a structure of my deplyement, what the best practice and give best performance and memory usage if I want to have a separate service per client : - define multiple virtual servers with one global "listen" section IP/port for all virtual server. - define multiple virtual servers and each server has its listen section IP/port difffrent - define single virtual servers and use if ....elsif....else to select the proper sql module. One Nas will use one virtual and server It can have more than 50 NAS and arround 20 to 50 simultanews connexion by NAS. Philemon Jaomalaza