Ovirt devel - Sep 2010 - Out of memory causes VM shutdown

I created a new VM today and it ran for a while before mysteriously
disappearing.  I logged in to the node it was running on to take a look at the
logs and it looks as though the VM was shut down because the node ran out of
memory.  This particular node has 8GB in it and was running 4 VMs (including the
crashed one).  The memory assigned to each VM was 4G, 1.5G, 512M, 256M.  It was
the 256M VM that was started last and that's the one that was shutdown. 
What are the memory requirements of the host OS?

Another thing I've noticed on the node is that as the memory usage increases
a lot of processor time is spent running ksmd.  Presumably it's spending
time reclaiming memory from buffers and cache.  Aren't buffers generally
used for disk buffering?  Does the host OS need to do this given the guest OS
will also be buffering the disks?

Cheers,
Justin.
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Hi,

Le 28/09/2010 11:04, Justin Clacherty a ?crit :
> I created a new VM today and it ran for a while before mysteriously
> disappearing. I logged in to the node it was running on to take a look
> at the logs and it looks as though the VM was shut down because the node
> ran out of memory. This particular node has 8GB in it and was running 4
> VMs (including the crashed one). The memory assigned to each VM was 4G,
> 1.5G, 512M, 256M. It was the 256M VM that was started last and that?s
> the one that was shutdown. What are the memory requirements of the host OS?
>
Wath's your qemu-kvm version ?
Indeed there was a memory leak on 12.3 corrected in 12.4.

Well you can use a network superviser (zabbix, nagios,...) to see that ;).
> Another thing I?ve noticed on the node is that as the memory usage
> increases a lot of processor time is spent running ksmd. Presumably it?s
> spending time reclaiming memory from buffers and cache. Aren?t buffers
> generally used for disk buffering? Does the host OS need to do this
> given the guest OS will also be buffering the disks?
>
More Memory more thing to analyse, more cpu.
You can control some parameters through : /sys/kernel/mm/ksm


Regards,
> Cheers,
>
> Justin.
>
>
>
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