Hi, This is a Centos 5.5 host with one xen guest. About 2 weeks ago, the host randomly lost network connection. By this I mean I could not connect to the services on it, or ping it. Also was the status of the guest. From serial console, I connected to the host, trying to see what happened. No clue (any error messages) in messages or dmesg. ifdown/ifup the interface did not help, either. Only rebooting was my only choice. Searching through Google, I got the information that some other guys met similar problem, and resolved by setting stp on with the bridge interface. I set it, too. And the problem still occurs. Any idea what I should check now? Thanks.
Hi,
On Wed, Oct 12, 2011 at 10:43 AM, Magicloud Magiclouds magicloud.magiclouds@gmail.com wrote:
Hi, This is a Centos 5.5 host with one xen guest. About 2 weeks ago, the host randomly lost network connection. By this I mean I could not connect to the services on it, or ping it. Also was the status of the guest. From serial console, I connected to the host, trying to see what happened. No clue (any error messages) in messages or dmesg. ifdown/ifup the interface did not help, either. Only rebooting was my only choice. Searching through Google, I got the information that some other guys met similar problem, and resolved by setting stp on with the bridge interface. I set it, too. And the problem still occurs. Any idea what I should check now?
So I assume that the problem occurs just with the xen domU and not with the dom0? And your solution is to reboot the domU (not dom0)?
With loosing network you mean you cannot ping your gateway ip and/or you cannot ping the domU from your gw?
You are running the latest kernel/xen packages provided by centos on your dom0 and domU?
How have you configured network on this server, can you post your configs (vif line in dom0 config aand newtork config files from the domU)?
And you are sure you have an unique MAC address in your LAN for your domU?
Best, Peter
On 10/12/11 12:43 AM, Magicloud Magiclouds wrote:
Hi, This is a Centos 5.5 host with one xen guest. About 2 weeks ago, the host randomly lost network connection. By this I mean I could not connect to the services on it, or ping it. Also was the status of the guest. From serial console, I connected to the host, trying to see what happened. No clue (any error messages) in messages or dmesg. ifdown/ifup the interface did not help, either. Only rebooting was my only choice. Searching through Google, I got the information that some other guys met similar problem, and resolved by setting stp on with the bridge interface. I set it, too. And the problem still occurs. Any idea what I should check now? Thanks.
When outage occurs, from the host these might be good things to look at and/or share with the list:
ip link brctl show arp -n (arp -n from your next-hop router too) tcpdump -ln -i peth0 (try some activity; e.g. ping out to router, ping in from router) tcpdump -ln -i br0 (more activity)
Depending on your xen bridge setup the bridge might be named eth0 or virbr0; peth0 might be different too.
Eric
On Thu, Oct 13, 2011 at 12:28 AM, Eric Searcy emsearcy@gmail.com wrote:
On 10/12/11 12:43 AM, Magicloud Magiclouds wrote:
Hi, This is a Centos 5.5 host with one xen guest. About 2 weeks ago, the host randomly lost network connection. By this I mean I could not connect to the services on it, or ping it. Also was the status of the guest. From serial console, I connected to the host, trying to see what happened. No clue (any error messages) in messages or dmesg. ifdown/ifup the interface did not help, either. Only rebooting was my only choice. Searching through Google, I got the information that some other guys met similar problem, and resolved by setting stp on with the bridge interface. I set it, too. And the problem still occurs. Any idea what I should check now? Thanks.
When outage occurs, from the host these might be good things to look at and/or share with the list:
ip link brctl show arp -n (arp -n from your next-hop router too) tcpdump -ln -i peth0 (try some activity; e.g. ping out to router, ping in from router) tcpdump -ln -i br0 (more activity)
Depending on your xen bridge setup the bridge might be named eth0 or virbr0; peth0 might be different too.
Eric _______________________________________________ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Sorry for the delayed reply. As you guys said, I checked the hardware, even replaced something. I think it is sure that the hardware is OK. The system is CentOS 5.5, and for some reason I cannot update it. The problem always and only could be resolved by rebooting.
-
Eric Searcy -
Magicloud Magiclouds -
Peter Peltonen