Hi,
I have JBC 1.4.1.SP3 in a JBossAS 4.2.0.
Cache configuration is this:

<?xml version="1.0" encoding="UTF-8"?>
<server>
 <classpath codebase="./lib" archives="jboss-cache.jar, jgroups.jar"/>
 <mbean code="org.jboss.cache.TreeCache"
 name="jboss.cache:service=ServicesCache">
 <depends>jboss:service=Naming</depends>
 <depends>jboss:service=TransactionManager</depends>
 <attribute name="TransactionManagerLookupClass">org.jboss.cache.JBossTransactionManagerLookup</attribute>
 <attribute name="IsolationLevel">NONE</attribute>
 <attribute name="CacheMode">REPL_SYNC</attribute>
 <attribute name="UseReplQueue">false</attribute>
 <attribute name="ReplQueueInterval">0</attribute>
 <attribute name="ReplQueueMaxElements">0</attribute>
 <attribute name="ClusterName">ServicesCache-Cluster</attribute>
 <attribute name="ClusterConfig">
 <config>
 .... jgroups config .....
 </config>
 </attribute>
 <attribute name="FetchInMemoryState">true</attribute>
 <attribute name="InitialStateRetrievalTimeout">15000</attribute>
 <attribute name="SyncReplTimeout">15000</attribute>
 <attribute name="LockAcquisitionTimeout">10000</attribute>

 <attribute name="EvictionPolicyClass">org.jboss.cache.eviction.LRUPolicy</attribute>
 <attribute name="EvictionPolicyConfig">
 <config>
 <attribute name="wakeUpIntervalSeconds">5</attribute>
 <region name="/_default_">
 <attribute name="maxNodes">500000</attribute>
 <attribute name="timeToLiveSeconds">86400</attribute>
 </region>
 </config>
 </attribute>
 <attribute name="UseRegionBasedMarshalling">true</attribute>
 <attribute name="InactiveOnStartup">true</attribute>
 </mbean>
</server>

Later, in our application, through code we set different eviction policies for different regions, in order to keep a rational cache size ratio.

We do this to activate regions of the cache, as we deploy services that use these regions:

 public void activateRegion(String strFqn) {
 try {
 RegionManager regionManager = getServiceCacheInstance()
 .getRegionManager();

 if (regionManager.getRegion(strFqn) == null
 || !regionManager.getRegion(strFqn).isActive()) {
 getServiceCacheInstance().registerClassLoader(strFqn,
 Thread.currentThread().getContextClassLoader());
 getServiceCacheInstance().activateRegion(strFqn);
 log.warn("Activating synchronization of region " + strFqn);
 }

 } catch (RegionNameConflictException e) {
 log.error("Activating region: " + strFqn, e);
 } catch (CacheException e) {
 log.error("Activating region: " + strFqn, e);
 }
 }

We also activate/deactivate different eviction policies for these regions. Like this:

 public void activateEvictionPolicy(String strRegion, EvictionConfiguration config) {
 if (strRegion != null || "".equals(strRegion)) {
 RegionManager regionMgr = getServiceCacheInstance().getEvictionRegionManager();
 Region region;
 EvictionPolicy eviction = null;
 try {
 if (regionMgr.hasRegion(strRegion)) {
 region = regionMgr.getRegion(strRegion);
 region.setEvictionConfiguration(config);
 log.warn("Region " + strRegion + " already had an eviction policy that has been updated now");
 } else {
 eviction.configure(getServiceCacheInstance());
 regionMgr.createRegion(strRegion, eviction, config);
 log.warn("Created new region " + strRegion);
 }
 log.warn("Setting "+ evictionPolicy.getType().toString()+ " eviction policy to region " + strRegion + ". Details: " + evictionPolicy);
 } catch (org.jboss.cache.eviction.RegionNameConflictException e) {
 throw new MyCacheRuntimeException(
 "Region name conflict for " + strRegion + ". Impossible to set an eviction policy.");
 }
 } else {
 log.error("There is not any eviction policy provided for region " + strRegion);
 }
 }

 }

My problem is:

The cache gets filled with about 2000 nodes, of 10 (key/value pairs) each, and for every node, I see there is a running Timer, which never gets discarded. At the end, my app fails being unable to create more threads.
I know this can be a memory problem, but I have set 1Gb heap, 384K thead size, and have a machine with 8Gb addresable memory, so my problem seems related to the number of threads being created.
For now, I only have one eviction policy set for one region, which holds the entire 2000 nodes, and I don understand why when a node gets evicted, or when most of them gets evicted, and node number drops to only 500, timers are over 2000.

Thanks.