Open Stack

I'd also keep an eye on local I/O... we've found this to be the resource which can cause the worst noisy neighbours. Swapping makes this worse.

Tim

> -----Original Message-----
> From: George Shuklin [mailto:george.shuklin at gmail.com]
> Sent: 21 April 2015 23:55
> To: openstack-operators at lists.openstack.org
> Subject: Re: [Openstack-operators] over commit ratios
> 
> It's very depend on production type.
> 
> If you can control guests and predict their memory consumption, use it as base
> for ratio.
> If you can't (typical for public clouds) - use 1 or smaller with
> reserved_host_memory_mb in nova.conf.
> 
> And one more: some swap sapce is really necessary. Add at least twice of
> reserved_host_memory_mb - it really improves performance and prevents
> strange OOMs in the situation of very large host with very small dom0 footprint.
> 
> On 04/21/2015 10:59 PM, Caius Howcroft wrote:
> > Just a general question: what kind of over commit ratios do people
> > normally run in production with?
> >
> > We currently run 2 for cpu and 1 for memory (with some held back for
> > OS/ceph)
> >
> > i.e.:
> > default['bcpc']['nova']['ram_allocation_ratio'] = 1.0
> > default['bcpc']['nova']['reserved_host_memory_mb'] = 1024 # often
> > larger default['bcpc']['nova']['cpu_allocation_ratio'] = 2.0
> >
> > Caius
> >
> 
> 
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