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Properly tuning your JVM can make a significant difference in performance. The following suggestions have proven to offer a good balance between performance, throughput, response time, and stability in most environments. As always, before performing any tuning you should understand the effect of each operation and take into account all the aspects of your environment.
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Oracle HotSpot Virtual Machine
The Sun Oracle Java Virtual Machine, HotSpot, offers a number of performance options. Before proceeding you should be familiar with the JVM, if you are not, you should stop reading and go review the document for the JVM.
Memory Management
All of the Java Shibboleth components attempt to keep as much frequently used information (like SAML metadata) cached in memory. While this caching is memory sensitive, in that if the JVM is running out of memory these caches allow the JVM to collect memory from them, providing a couple gigabytes of memory to the JVM is recommended. Additionally, the Identity Provider depends on a significant number of classes which can cause the permanent generation to be exhausted.
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