You can modify the size of a vRealize Hyperic cache by editing an element in the ehcache.xml file. Generally, only cache sizes need to be changed.

The ehcache.xml file can be found under server-n.n.n-EE\hq-engine\hq-server\webapps\ROOT\WEB-INF\classes\.

Each cache is defined with an entry like

```<cache name="DerivedMeasurement.findByTemplateForInstance"
maxElementsInMemory="10000"
eternal="true"
timeToIdleSeconds="0"
timeToLiveSeconds="0"
memoryStoreEvictionPolicy="LRU"/>
```

You might need to iterate the cache size until you find the optimal setting.

## Caches that you Cannot Change

There are two caches that you cannot configure:

• org.hibernate.cache.UpdateTimestampsCache, which is managed by Hibernate

• AvailabilityCache, which is managed by the vRealize Hyperic server