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I have a node running 30 xen vps. When I ping my node IP, it's okay, but when I ping the guest IPs, there's high packet loss. Even when I login to my node to ping guests, there're high packet loss.

I've checked iptables, there's no rule for this, because when I stop iptables, packet loss still happens.

I've tried reboot the server but still not solved, anyone has any idea?

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If you start a single guest do you get the same problem? Perhaps one of them is saturating the interface? – Paul Sep 27 '11 at 6:34

First thing to take a look at is xentop and drill down into network usage.

Beyond that you can also take a look at iftop to see if you notice any unusual traffic.

There are several common symptoms and problems outlined here:

And several approaches to optimize things:

Take a look at those and do so more troubleshooting and data collection. That guide ( has other general suggestions as well that should apply to Xen in general.

Some things to think about looking at include CPU utilization or other over constraint symptoms (low memory, swapping, etc.). The other thing that is useful to think about is what type of guest is it (PV or HVM)? What driver is being used? Is there a better set of NIC configuration options that could be used?

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