The frontrunner in distributed caching is the open source code Memcached, pronounced Memcache-D. A set of startups have sprung up around the open source project to build products out of Memcached, including Northscale, Schooner and Gear6.
The runner up in distributed caching, however, is Greg Luck's open source project, Ehcache, part of Terracotta since last August. Ehcache 2.1 governs the distributed random access memories of a server cluster on behalf of Java applications.
It is now integrated with Terracotta, the firm's core product, which manages Java virtual machines across a server cluster for Java applications, allowing them to scale out to more end users than if they were running on a single server.
The 2.1 upgrade of Ehcache became available May 25. It includes a plug-in monitor that provides a real-time view of how the cache is being used and its key performance metrics, such as application response time or transaction processing time. Obtaining a view of Ehcache performance gives feedback and specific metrics that can identify bottlenecks in an application and how to avoid them in future applications, said Amit Pandey, CEO of Terracotta, in an interview.
"We need to get the data close to the application before it is too late" for the application to meet performance expectations in the face of rising user demand, he noted. Having a monitor reporting on operations will help developers do that.
Ecache 2.1 includes expanded support for IBM WebSphere, so that the Java application server can take advantage of all the features of the caching system while running a Java application. Additional support for WebSphere was added to Terracotta itself. Terracotta clusters Web sessions, and that feature is available to WebSphere to enable faster application response to more users. The Web session clustering is already available to Oracle's WebLogic application server, Red Hat's JBoss application server, Apache Tomcat Servlet engine and Jetty, a lightweight open source Web application server backed by WebTide.
In addition Ehcache 2.1 included configurable service level agreement parameters that set the system to produce results within the defined settings. Disk drives fail, networks take on latencies and databases slowdown. When they do, Ecache responds to maintain the SLA and alerts managers on an impending problem. "You can respond to slowdowns much better than you could before," Pandey said.
The 2.1 release includes support for JTA, the Java transaction protocol, that assists the application in a executing a full transaction write and reports back to the application when a transaction is completed, Pandey said.
Terracotta with Ehcache ranges in price from $5,000 to $12,000 per application node or cluster server. Ehcache remains available as a separately downloadable piece of open source code.
Ehcache was previously upgraded March 15, when the 2.0 version was released.