Normally, a GTM Performance domain balances load based on estimates produced by NSD. NSD builds load averages from nameserver logs over a period of about a week, with updates occurring once or twice a day (see Nameserver demand estimation). Ghost load provides an alternate way to collect load feedback from a GTM Performance domain.

GTM ghost load provides load feedback and reporting for properties or domains with ghosts as their primary audience and uses GTM to load balance ghost-to-origin traffic. Because ghosts (Akamai servers) often pre-fetch popular content, their load is extremely variable. The benefit of enabling this option on a ghost load domain is that load updates are reported every few seconds and the estimates always include the current set of ghosts in a region.

Reports on ghost load occur per property. Each Performance property with ghost load enabled is assigned a unique ID number. GTM keeps a list of these Performance properties and periodically reports the load on them by ID number.

Enable ghost load feedback

To specify a ghost load domain, you need to enable ghost demand reporting for at least one Performance property in that domain. For ghosts that need to resolve the ghost load-enabled Performance property, you need to specify if they are on Freeflow DNS or ESSL.

Ghost load feedback is enabled in the portal at the property level only for Performance properties.

To enable ghost load feedback for a domain’s Performance property:

1. In the Traffic Domains Management page, click the Domain name.

2. In the Properties list, click the Property name of the Performance property.

3. Expand Property Basic Settings.

4. Select Ghost demand reporting.

5. Click Add to Change List.