Terracotta is Network Attached Memory (NAM). NAM is best suited for storing what we like to call scratch data. Scratch data is defined as object oriented data that is critical to the execution of a series of Java operations inside the JVM, but may not be critical once a business transaction is complete. Some examples of scratch data include business workflow state (which step of the flow is the system currently working on), or HTML form data that is being validated by a web application before a database record is created or updated.
How Terracotta Works
The Terracotta architecture is designed to minimize network chatter, guarantee that there can be no split-brain, provide the absolute maximum of operator control, all while providing 100% High Availability and no Single Points of Failure.
How Terracotta Scales
Terracotta provides Java applications with a runtime environment that allows developers to trust critical parts of heap as reliable and capable of scaling through shared access across multiple machines. The technology hinges on a clustering server that keeps a shared view of objects across JVMs. The key question around scalability of a Terracotta-based application can only be answered by analysis of the architecture and the alternatives.
