In Avi Elastic HA N+M mode, the N value represents the minimum active scale required for a Virtual Service, while M represents additional capacity maintained for resiliency. Broadcom's Avi documentation explains that in N+M Elastic HA, M is the number of additional or buffer Service Engines that the Avi Load Balancer Controller maintains in the Service Engine Group. These buffer Service Engines provide spare capacity for failover, scale-out, and placement flexibility. This is separate from the maximum number of Service Engines in the group, which defines the upper limit of SEs that can exist. It is also separate from the maximum number of Virtual Services per Service Engine. Therefore, the ''M'' in N+M Elastic HA refers to the number of buffer Service Engines.