[Xen-users] RE: network problem with 50 domUs

[이동규 <dongq.lee@xxxxxxx>]

Sorry for insufficient information.

I am using 3.0.3 xen version on Centos5.2 and the machine has 16 GB RAM and 256MB is allocated to each domU (PV)

All domUs are attached to singe bridge (xenbr1) and they are all PVs. kernel version is 2.6.18-92.1.22.el5xen.

 

When I created 50 domUs in a machine, their network connections were made properly and worked just fine.

However, a few hours later, domUs’ network suddenly did not work even if all network configurations and

virtual bridge configurations remained same as before.

/var/log/message file (of dom0)  was filled up with the following messages;

 

May 17 06:11:04 ibmn2216a45 kernel: xen_net: Memory squeeze in netback driver.

May 17 06:11:09 ibmn2216a45 kernel: printk: 4 messages suppressed.

Their network problems seemed to be solved after rebooting domUs, but it did not last long. Only a few hours.

 

Please explain me why it is happening. Thank you in advance.

From: Fischer, Anna [mailto:anna.fischer@xxxxxx]
Sent: Saturday, May 16, 2009 1:51 AM
To: 이동규
Cc: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: RE: network problem with 50 domUs

 

It worked after you rebooted Dom0, or DomU? What Xen version is this, and what Dom0 kernel version? How do you know about the memory limit issue? What error messages do you get? Can you post that error log? How much RAM does the machine have, and I assume you are not using HVM guests? Are you attaching all guests to only a single bridge?

 

From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of ???
Sent: 13 May 2009 22:49
To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-users] network problem with 50 domUs

 

I have created 500 domUs in 10 physical servers. Each server contains 50 domUs.

After I have started 50 domUs using shell script which used for loop and xm create,

Every domU was successfully started and listed up with.

However, domU network did not work.

The interesting thing was that they became working after reboot manually. It seemed that Dom0

did not have enough memory to set virtual bridge properly.

I don’t really know why it happens.

Please explain more about it. Thank you in advance.

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