Configure overflow criteria based on one of these factors:

• Entry count
• Absolute memory consumption
• Memory consumption as a percentage of the application heap (not available for server subscription queues)

Configuration of region overflow:

<!-- Overflow when the region goes over 10000 entries -->
<region-attributes>
  <eviction-attributes>
    <lru-entry-count maximum="10000" action="overflow-to-disk"/>
  </eviction-attributes>
</region-attributes>

Configuration of server's client subscription queue overflow:

<!-- Overflow the server's subscription queues when the queues reach 1 Mb of memory -->
<cache> 
  <cache-server> 
    <client-subscription eviction-policy="mem" capacity="1"/> 
  </cache-server> 
</cache>