Linux I/O bottleneck with data-movers

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http://serverfault.com – I have a 24 core machine with 94.6GiB RAM running Ubuntu server 10.04. The box is experiencing high %iowait, unlike another server we have (4 cores) running the same types and amounts of processes. Both machines are connected to a VNX Raid fileserver, the 24-core machine via 4 FC cards, and the other via 2 gigabit ethernet cards. The 4-core machine currently outperforms the 24-core machine, has higher CPU usage and lower %iowait. In 9 days uptime, %iowait averages at 16%, and is routinely above 30%. Most of the time CPU usage is very low, around 5% (due to the high iowait). There is ample fre (HowTos)