If you cannot provide load feedback as described in Performance with load feedback, you can configure GTM to load balance without it. This mode relies heavily on the nameserver demand estimates (see Nameserver demand estimation), based on how often nameservers revisit Traffic Management nameservers to refresh cached DNS resolutions. GTM attempts to assign traffic so that the sum of the nameserver demands allocated to each of your data centers respects the traffic weights you configured, subject to the leeway allowed by the load imbalance factor. This method works best for properties that have large user populations distributed widely throughout the world. It doesn't work so well for very small or concentrated user populations.
It's Important that you remember these points about load balancing without load feedback.
It's based purely on historical estimates of client demand behind nameservers.
It doesn't take into account daily load fluctuations.
It can't take into account anomalies such as a large ISP deploying a new nameserver serving thousands of clients, as it can take a week or more for new nameserver loads to propagate through NSD.
If you require precise load balancing that reacts quickly to changing loads, consider using load feedback.
Updated 6 months ago