Avoiding Excessive CoS Definitions

Directory Server optimizes CoS when one classic CoS definition entry is associated with multiple CoS template entries. Directory Server does not optimize CoS if many CoS definitions potentially apply. Instead, Directory Server checks each CoS definition to determine whether the definition applies. This behavior leads to performance problems if you have thousands of CoS definitions.

This situation can arise in a modified version of the example shown in Figure 4–6. Consider an Internet service provider that offers customers delegated administration of their customers’ service level. Each customer provides definition entries for standard, silver, gold, and platinum service levels. Ramping up to 1000 customers means creating 1000 classic CoS definitions. Directory Server performance would be affected as it runs through the list of 1000 CoS definitions to determine which apply. If you must use CoS in this sort of situation, consider indirect CoS. In indirect CoS, customers’ entries identify the entries that define their class of service allotments.

When you start approaching the limit of having different CoS schemes for every target entry or two, you are better off updating the real values. You then achieve better performance by reading real, not CoS-generated values.