Wednesday, June 18, 2008

Ganymede: Ready for Launch

Matt tested our shiny new Gigabit connection for Ganymede yesterday by removing all the mirrors from our list, in an event we call "Mirror Appreciation day". Not only does it allow us to tweak TCP stacks, routers and web server configs before a huge rush of traffic, it allows us to see how much bandwidth the Eclipse Foundation would need to pay for if we didn't rely on mirrors.

Looking at the red line, you can see the drastic bandwidth increase as the list of mirrors was cleared. After about 1 hour [1] we peaked the chart at 400 Mbps (300Mb here, plus our regular 100Mb colo port was saturated at the time) and when I saw our total bandwidth reach 420Mbps, I put on the brakes, limiting the Gigabit port to 200Mb (point [2]). The mirror list was re-populated a few hours later and bandwidth returned to normal.

If we didn't have mirrors, we'd need at least 400Mbps of permanent bandwidth (we currently have 80 Mbps now), and we'd likely need at least a full Gigabit pipe for Ganymede.


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