Bug#625217: xen-linux-system-2.6.32-5-xen-amd64: Heavy load on domU causes dom0 to run out of memory

[Sebastian Hofmann <sebastian.hofmann@sourcepark.de>]

Hi Ian,

Thanks for your reply.

In the meantime I found out that I forgot to change the device name of
the swap devices in fstab of the domUs when upgrading to XEN 4.0. So in
fact all domUs had no swap space at all.

I think this might be the problem that a domU ran out of memory...

However, the dom0 always had a swap space, so the question is still why
the dom0 also runs out of memory.

>> May  2 16:05:26 hercules kernel: [ 1768.319877] nrpe invoked oom-killer: gfp_mask=0x200da, order=0, oom_adj=0
>> May  2 16:05:26 hercules kernel: [ 1768.319883] nrpe cpuset=/ mems_allowed=0
>> May  2 16:05:26 hercules kernel: [ 1768.319886] Pid: 2118, comm: nrpe Not tainted 2.6.32-5-xen-amd64 #1
> 
> Am I right that nrpe is part of nagios? (it's probably just the unluck
> process so tells us nothing really)

You are right - this log message was just an example of what happens.

> What sort of load are the domUs experiencing? i.e. CPU, network, disk
> etc.

CPU and memory consumption

> What does your storage stack look like? (are you using LVM, iSCSI, DRDB,
> SW RAID, filesystems etc).

SW Raid

> Are you running anything interesting in domain 0 other than the Xen
> toolstack, nagios, sshd etc?

nagios nrpe, sshd, fail2ban-server, bacula-fd, rsyncd, postfix

> What does /proc/meminfo look like after a fresh boot?
> 
> Lastly, please can you provide a dmesg log of the initial bootup.

I will provide the requested information as soon as I can reboot the
machine.

We also will do some tests with high load again on the domUs with
enabled swap space to see if the problem still exists.

> Cheers,
> Ian.

Thanks
Sebastian