Question: Is Ehcache a Distributed Cache System?

Answer

Yes, Ehcache is a distributed caching system. It's an open source, standards-based cache that boosts performance, offloads your database, and simplifies scalability. Ehcache is robust, proven, full-featured, and integrates with other popular libraries and frameworks.

In its distributed configuration, Ehcache uses Terracotta server array to provide cache coherence (consistency) across multiple nodes in a cluster. This allows the application to see a single, coherent view of the cache data, which is extremely valuable in multi-node environments.

Here's an example of how you might configure Ehcache for distributed caching:

<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="ehcache.xsd"
         updateCheck="true"
         monitoring="autodetect"
         dynamicConfig="true">

    <cacheManagerPeerProviderFactory
        class="net.sf.ehcache.distribution.terracotta.TerracottaClientBootstrapCacheManagerPeerProviderFactory"
        properties="terracottaConfigUrl=localhost:9510"/>

    <defaultCache
        maxElementsInMemory="10000"
        eternal="false"
        timeToIdleSeconds="120"
        timeToLiveSeconds="120"
        overflowToDisk="true">
        <terracotta/>
    </defaultCache>

    <cache name="sampleCache1"
           maxEntriesLocalHeap="10000"
           eternal="false"
           timeToIdleSeconds="300"
           timeToLiveSeconds="600"
           overflowToDisk="false">
        <terracotta/>
    </cache>
</ehcache>

This configuration sets up a distributed cache named 'sampleCache1', using a Terracotta server at 'localhost' on port '9510'.

Remember to add proper dependencies in your project.

Please note: the use of distributed Ehcache requires Terracotta servers. Always refer to the latest documentation for any updates or changes.