Networking upgraded the network reinforcing the online to offline (HPSS) path with a layer 3 structure made of Arista's switches. The topology changed and so was the hash (a hash is used to send data streams along different path and take advantages of it, essentially achieving data path bandwidth balancing).

A test was requested on 2014/07/27 (to be done on the 28th) - Jeff helped and fired his data transfer processes. The following map of the network shows the diagram and roughly explains what we tested (follow the A, B, C).




A few notes:

• Don't get confused by the arrows showed like this "=><=" - it simply "a" way of showing a up/down path (instead of two arrows in // all the way, goes 1/2 way in each direction)
• Essential component is to realize that at B, we have a fairly good split of data being send toward s806 switch and s807 switches
• Then from there, the split again happens fairly symmetrically - the numbers on top of the arrows are instantaneous values. To really see the balancing, one need to check the detailed plots below (only two are showed as they all look the same after s80x)

Averages are pretty close - we are good.