Directory Server allows you to strictly control the use of memory for cache purposes so that less memory is used. You specify a low and high threshold for dynamic memory use. When this threshold is reached, Directory Server attempts to free memory from the suffix entry caches and to keep memory use under control. If the server reaches the high threshold, the server goes into aggressive mode to free memory. Performance is only effected when the high threshold is reached.
This feature provides two configurable thresholds: a soft threshold and a hard threshold. When the soft threshold is reached, Directory Server attempts to free memory concurrently with other operations. When the hard threshold is reached, operations on the cache are prevented while memory is being freed. These two thresholds are defined by two server properties:
heap-high-threshold-size specifies the hard threshold.
heap-low-threshold-size specifies the soft threshold.
See the server(5dsconf) man page for details on the two server properties.