By clustering the JVM via its quick deployment mechanisms, Terracotta is carving out a new niche in Java infrastructure efficiency. The clustering for JVMs goes beyond load balancing to provide session replication for large or small applications. Terracotta is basically offering clustering for dummies (no offense intended), making framework users into power deployers. I saw a demo and its pretty amazing how quickly clustered deployment occurs using the Terracotta approach.
The virtualized clustering for Java benefit that Terracotta is pioneering also sets the stage for the creation of specific software appliances that greatly simply robust Java deployment for developers who are primarily comfortable focusing on the development framework level, be it Tomcat or Spring. Terracotta 2.0 is coming out of the gate with support for Tomcat and Weblogic, but they apparently plan to announce support for Spring as soon as next week.
I'm told that Sun and IBM have had clustered JVM initiatives largely focused on the VMWare level, but that those trees have yet to bear fruit. BEA Systems has also been doing work to further exploit the JRocket JVM as robust platform. As Sun Microsystems seems intent on loosening its grip on Java licenses, it will make even more sense for JVM-oriented architecture to emerge as a strong development and deployment strategy for more developers and across more frameworks.
I can also see where such JVM-level platform support would fit nicely with SOA, in that a service alone could be offered on a clustered JVM basis and be flexibly supported in terms of dynamic resource provisioning and high-efficiency utilization of resources. Very cool.
I also like the idea of bringing this benefit into the multi-tenancy-intense datacenter environments that those who support outsourced IT operations are building and refining. In a business where utilization efficiency is king, reliability essential, and SOA an imperative, the clustered JVM model seems a no-brainer.
While Terracotta offers free downloads of the clustering offering, it does charge when the ramp-up kicks in. Check out the pricing carefully, but the value seems quite significant, especially for environments where many apps are being added, rapid deployment is a must, user demand is variable, and total cost of operations is a competitive factor.