nova-compute can send up to ~9 queries / minute / server to neutron with the default setting of 60. As we look at scaling to ever greater numbers of computes in a cluster (the scale team has gone up to 1000), this can put a significant load on neutron (in the case of 1000 computes, up to 150 req/s).

In previous discussions with the nova team, it was agreed that setting this to zero in the modern era should not be a problem. So I think we should consider making this the default. If not, then documenting configuration / tuning recommendations for this setting, especially since this tends to affect bigger installs the most.