For a bit more information on CMT, please read what Allan Packer, SUN, has written more on CMT hardware on his blog.
Looking at MySQL Cluster, and in particular the data nodes, they like:
- Fast CPUs (two cores per data node), 2+GHz CPU.
- RAM, as fast as possible.
- Fast disks (SSD would be great fun to try in combo with Cluster). Fast disks are important especially for write-heavy applications.
How to generate a lot of parallel load? Well, use Sun CMT in the application layer (mysqld + app/web servers).
This is also inline with the trends in the industry where you don't perform heavy operations on the precious CPUs used by the storage layer, but rather do computation etc at the application layer. An excellent fit for SUN CMT, which has ample of threads to throw at a problem! Also, SUNs Java technology is optimized for CMT making it an extremely good idea to use Glassfish as the app server in this scenario.
Now, bear in mind that all nodes making up a MySQL Cluster (6.2 and 6.3) requires the same endianess, so you can't combine CMT with AMD/Intel architecture at the storage level yet (this got to get fixed).
This means I would use two of these for the data nodes and the final architecture would look as follows which would be nearly indestructible (with redundant BIGIP Load balancers, switches, data nodes etc).