I am in a large enviornment with 3000+ Vms which is expanding. I need to determine what subnet size to use for future vlans that are created. I can use /24 with 254 IPs, /23, /22, etc.
The more VMs I have on a subnet, the more broadcast traffic goes around the network. Every host has to process the broadcast frames when it has VMs on that subnet and drop them or pass them in to a virtual machine, eating up CPU time on my ESXi hosts. The larger the subnet, the more ESXi hosts have to process broadcast frames.
How do I know if I am at risk of having too much broadcast traffic? At what point should I limit the size of subnets to make sure I don't have too much broadcast traffic? Should I limit it to /24, /23 or /22? How big is too big in terms of too many broadcasts?