Directory Server offers performance and scalability improvements for Access Control Instructions. The improvements include better memory management. The improvements also include support for macro ACIs. Improvements notwithstanding, Directory Server uses significant system resources to evaluate complex ACIs. Extensive use of complex ACIs can therefore negatively impact performance.
Macro ACIs help you limit the number of ACIs used. By limiting the number of ACIs, you render access control easier to manage and reduce the load on the system. Macros are placeholders that represent a DN, or a portion of a DN, in an ACI. A macro can be used in an ACI target, in an ACI bind rule, or in both. When Directory Server receives a request, it checks which ACI macros match against the resource targeted for the resulting operation. If a macro matches, Directory Server replaces it with the value of the actual DN. Directory Server then evaluates the ACI normally.
Testing has demonstrated that a Directory Server instance can support more than 50,000 ACIs. Nevertheless, keep the number of ACIs as small as possible. Keeping the number of ACIs small limits negative impact on performance. Keeping the number small also reduces the complexity of managing access controls. For deployments involving complex ACI environments, consider using Directory Proxy Server to provide some access control features.