[cpa]

Any idea why the results are not symmetrical? Upload from Virginia to California is twice as fast as from California to Viriginia (and it's even worse with US <-> Japan).

Are there strategical interests to not have a symmetric link?

[datasage]

Actually, the results are reverse from what you said (y-axis is the origin). It likely has to do with traffic congestion coming out of each datacenter. Virginia has by far the heaviest use out of all the datacenters.

[Xylakant]

Maybe the link is symmetric, but the traffic flow is not - so in one direction the intertubes are more clogged.