Hi everybody

I've a very big network problem with some server running CentOS with KVM and some linux-like VMs on the top of it. The vm's network is bridged with a physical dedicate NIC (an Intel PRO/1000) with 2.4.14-NAPI driver (but the problem persists with various versions of the driver) and the CentOS version is 6.4 (same problem with a 5.7 sever) with all the last updates. Randomly I get a lots of overruns on the vnet device on the physical server ad obviously some packet were lost in the VM.

brctl show br1 bridge name bridge id STP enabled interfaces br1 8000.002655e7590d no eth3 vnet1

ifconfig vnet1 vnet1 Link encap:Ethernet HWaddr FE:54:00:BF:27:12 inet6 addr: fe80::fc54:ff:febf:2712/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:13358349859 errors:0 dropped:0 overruns:0 frame:0 TX packets:21831525660 errors:0 dropped:0 overruns:1746068 carrier:0 collisions:0 txqueuelen:500 RX bytes:5080769358430 (4.6 TiB) TX bytes:16548002754111 (15.0 TiB)

As you can see there are a huge numbers of overruns also if the physical NIC is dedicate solely to this VM and the network traffic is less than 150Mbps. The server is a quite new machine (HP DL120 G6) but I have the same problem on an old DL360 G5 (but this is running about 10 vms). What can I do to solve the problem? My idea was to use the KVM passthrough functionality for the network device, but this method isn't good for a server that runs more than 2 vms as my 360G5...

Thanks Beppe

PS sorry for my bad english