Megabit/Gigabit Upgrade
for a Download Server

1. Test with 100 MBit Network:

With the 100 MBit card we hit the ~97.000 kbit/s barrier for the server bandwidth (as expected) when the ramp test reaches about 200 users. Until about 100 users each user was able to achieve almost the full 100 Mbit bandwidth of his own. With more users the per-user-speed degrades (T1) until with about 200 users the server reaches its 100Mbit/s limit. At this point the requests can't be answered fast enough, requests begin to pile up and the speed per user almost reaches zero. But looking at the request times (T2) the users experience only a little slowdown until about 200 users are active and request come in faster than they can be answered.

2. Test with GigaBit Network:

As expected this test does not hit a limit of the server bandwidth and reached 120 MBit/s. During the complete test the bandwidth available per user is at about 350 MBit/s. The click times (times that each user experienced to download one file) is at about 30ms during the complete test.

Conclusion

With a 100 Mbit connection this server can not support more than 100 users without a deterioration of performance per user. Using a Gigabit network solved the problem.

Test Setup