Data Center Network Performance Matters
TCP, delay, and window size can all play the same role inside a data center network.
It is a well-established fact that latency in the data center matters. According to this Network World report, a number of issues, including poor TCP window sizes and slight changes in delay, can make a huge difference in throughput.
""It's been an interesting week at work. Make that two weeks. For the last couple of weeks, we have been working on a throughput performance issue between a very expensive Fujitsu M8000 server and network storage over our 10GbE network. The M8000 was accessing storage via NFS over TCP. Cutting to the end of the story, it wasn't (well, at this point, I should say it 'isn't') a network issue, despite the ignorant claims to the contrary. As most of us network engineers know, as soon as something is slow, people will proclaim 'it's gotta be a network issue'. It took a while to dispel that theory (sadly, again) and focus on what appears to be the problem now which is drivers and patches on the server."