Try Tangosol Coherence (Score 1)

If you are working with multiple servers, you should look at Coherence.

We do a lot more than clustering app servers. Our product serves as an in-memory data store in a clustered application tier. If you have experience with high-scale J2EE applications, you'll probably have experienced what I call the "single point of bottleneck": the database. For some of our customers, we've reduced their database usage by 99.9%+ and their overall infrastructure costs by over half. With the replicated cache, each application server has all the "cached" data locally, so access is instantaneous. With our concurrency features, the data integrity is maintained, whether on a single server or replicated across 100 servers. With our distributed cache, if you have 100 servers each caching a half GB of data, you have a 50GB cache!

Other features include support for grid computing, cache querys, and more. We've focused heavily on making sure that our clustering is fault tolerant and extremely reliable.

Check out how the TheServerSide created a single cluster out of multiple vendor's app servers using Coherence. You may not need it for your application, but it shows what you can accompish.

Gene Gleyzer
Tangosol, Inc