The customer is in the online gaming industry and we are building a platform based on MySQL Cluster where we are consolidating a number of applications. Workload is mainly inserts, updates, pk reads, and index scans (quite frequent), and a few joins. The cluster handles the transient data (current working set), and is replicating to a long term data store (following this approach), and we are also feeding other back-end support systems from this.
The cluster (>8 computers) is interconnected with Dolphin DX adapters. Computers are SUNs Nehalem based servers (Intel XEON E5540). The cluster (7.0.6) consists of 4 data nodes each having 32GB of RAM, plenty of RAID 1+0 storage, and >4 mysql servers. All running on the Nehalems.. It is so sweet :)
So much did things improve with the DX adapters over Gig-E? Just by plugging it in we got an overall 2.5-3x performance improvement (throughput up, response times down). I love it. Now we will continue optimizing the setup, schemas, queries etc to really find out.
I can really recommend the investment in DX adapters (remote memory access is faster than local disk) if you are after the top-notch performance , and the company behind it, Dolphin ICS is really fantastic to work with. If the DX switch would fail, then it will automatically fall back on the Gig-E adapters, transparently, and no service interruption (you or the applications don't notice a thing, except that performance drops).
Note: Dolphin ICS' adapters offers a socket interface. Thus, any TCP/IP application can benefit from the low latency and high bandwidth.