IBM BS029ML Self Help Guide - Page 170

Access control data management service For improved performance during Portal access control lookups, you should avoid using LDAP directories configured with nested groups (a group or groups inside a group). If this is the case and your LDAP directory is not configured with nested groups, then the attributes shown in Table 5-16 can be modified to allow improved performance during user searches by limiting the search to the first level of the group. Table 5-16 Access control data management service Parameter Default value accessControlDataManageme true nt.enableNestedGroups Recommended value false If no nested groups exist in your LDAP or Custom User Registry, the parameter documented in Table 5-16 can be modified. Consult the Information Center for additional parameters that can be modified. Cache Manager Service Caching is fundamental to the performance of WebSphere Portal Server. For this reason Portal implements several additional internal caching mechanisms above those found in the underlying WebSphere Application Server instance. For maximum flexibility the characteristics of the majority of these cache instances are configurable through the settings found in the Cache Manager Service. In most environments the default out-of-the-box settings will suffice, leaving modifications only necessary if a high number of cache misses are observed for a concerned entry when viewed with Performance Viewer. However, one important parameter found under the Cache Manager Service property settings is the cacheglobal.size directive. At first glance this setting would appear to be a catchall for any caches not specified further on in the file. Table 5-17 Cache Manager Service Parameter Default cacheglobal.enabled true cacheglobal.size (number of entries) 1000 cacheglobal.shared false cacheglobal.replacement moderate cacheglobal.admit-threshold 0 cacheglobal.lifetime Recommended true. Increase if necessary. See notes and InfoCenter. See notes and InfoCenter. See notes and InfoCenter. See notes and InfoCenter. Under certain conditions typically associated with aggressive load testing, the global cache can experience thrashing associated with implementing a Least-Recently-Used (LRU) eviction strategy. A worst case load test scenario, for example, might log in 1000 users, at which point in time the global cache will become fully occupied. By increasing the cacheglobal.size value from the 1000 default entries, this problem can be overcome. Careful consideration should nevertheless be exercised, as additional cache entries will consume more Java memory. It also follows that Portal cluster deployments support an accumulative number of entries based on the number of server members participating in the cluster. 156 IBM WebSphere Portal V6 Self Help Guide