continuous packet drops in KVM guests

Hello gentlemen,

I'd like to ask somebody more experienced then me for help. I've got machine with 4 running KVM guests. The host is moderately loaded (load_avg ~4-5), same applies for the guests.

On all of those guests, I see remarkable amount of dropped packets for no obvious reason. Packets are being dropped even during nonworking hours, when load drops to almost 0.

Host is 8core box with 48GB RAM running x86_64 RHEL6 based, kernel 3.0.60, qemu-kvm-1.4.0. guests are SMP (2-4CPUS) RHEL6 based x86_64, kernel 3.0.51.

I'm using bridge + virtio for guest networking.

I tried to increase receive buffers etc, to no avail. Still few packets are dropped every second. Sometimes it's visible even on ssh session..

What could be the culprit of this? Didn't anyone have similar problem?

thanks a lof for any hints..

BR

nik

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