You can monitor the memory consumed by your entry cache using the entry-cache-info property in the periodic stats logger. You can retrieve the monitor entry over LDAP by issuing a search on baseDN="cn=monitor" using filter="(objectClass=ds-fifo-entry-cache-monitor-entry)". For example, the entry might appear as follows:
dn: cn=Static Group Entry Cache Monitor,cn=monitor 
objectClass: top 
objectClass: ds-monitor-entry 
objectClass: ds-fifo-entry-cache-monitor-entry 
objectClass: extensibleObject
cn: Static Group Entry Cache Monitor 
cacheName: Static Group Entry Cache 
entryCacheHits: 6416407 
entryCacheTries: 43069073 
entryCacheHitRatio: 14 
maxEntryCacheSize: 12723879900 
currentEntryCacheCount: 1 
maxEntryCacheCount: 175000 
entriesAddedOrUpdated: 1 
evictionsDueToMaxMemory: 0 
evictionsDueToMaxEntries: 0 
entriesNotAddedAlreadyPresent: 0 
entriesNotAddedDueToMaxMemory: 0 
entriesNotAddedDueToFilter: 36652665 
entriesNotAddedDueToEntrySmallness: 0 
lowMemoryOccurrences: 0 
percentFullMaxEntries: 0 
jvmMemoryMaxPercentThreshold: 75 
jvmMemoryCurrentPercentFull: 24 
jvmMemoryBelowMaxMemoryPercent: 51 
isFull: false
capacityDetails: NOT FULL: The JVM is using 24% of its available memory. Entries can be 
added to the cache until the overall JVM memory usage reaches the configured limit of 
75%. Cache has 174999 remaining entries before reaching the configured limit of 175000.

By default, the entry cache memory is set to 75%, with a maximum of 90%.