I have a Debian box up and running with KVM and two guest machines, which I will refer here as Tux-A and Tux-B, both bind to the same physical network card of the Host via a bridged connection.
The problem is that Tux-A shows evidences of some sort of bandwidth limit uploading to the outer network:
- upload from Tux-A to ip on same Private Network = 45Mb/sec
- upload from Tux-A to ip on outer Public Network = 150Kb/sec
- upload from Tux-B to ip on same Private Network = 45Mb/sec
- upload from Tux-B to ip on outer Public Network = 3Mb/sec
given these values I presume that:
- no limit is set on top via KVM to the upload bandwidth (otherwise Tux-B should also be slow uploading to public network)
- no limit is set on top of Tux-A (otherwise Tux-A should also be slow uploading to private network)
just to complete the scenario:
- no iptables is active on the Debian host nor Tux-A (double checked and on both machines the services are disabled)
- no other specific service in terms of traffic shaping is active on both the Debian host and Tux-A (no tc, no shorewall, no KVM parameters tweaking, nothing)
- the router that connects to outer network is (said to be) uncapable of any form of traffic shaping (and I have no evidence of that capability in the admin area)
So in my (very very humble) opinion, if it's something set directly on Tux-A, and if on Linux everything is a file, is there somewhere among Linux's system files where this kind of limit can be set? somewhere in /proc, /sys, or such? or can someone suggest some other way to solve this situation?