Hi! Does a router VM have another kind of network rate limitation besides the one from the network offering?
We have the network offering set to 4000 Mbit/s which is resembled by XenServer through limiting the interface bandwidth to 500MByte/s (checked that). With unrouted traffic within a CloudStack network (between instances running on different nodes that all have 10 GbE links), the instances peak at the configured 4000 Mbit/s (so, as expected). When doing routed traffic between different CloudStack networks (passing 2 router VMs), the same test peaks at around ~920 Mbit/s while the router VM CPU shows to idle about 99% (25k interrupts/s). The instances used for testing as well as the router VMs run on Citrix XenServer 6.0.2 and are all using xen_netfront as the virtual ethernet driver (which does not even supply a speed value to the VM). I've also looked for any kind of tc/iptables rules on the router VM but couldn't find any that seem relevant for this issue. Ideas, anyone? :-) Cheers, Wolfram
