"The in-memory technologies that Pentaho is using in its 4.1
release were not built by Pentaho. Rather, they're leveraging Red
Hat's InfiniSpan as well as the memcached open source projects.
The clustering also enables high-availability of the cached
data. For example, there could be two copies of a data set
available at all times. Fyfe noted that the system takes care of
high-availability and failover too.