[pve-devel] adding a vm workload scheduler feature

[Dietmar Maurer]

> On November 17, 2015 at 4:43 PM Michael Rasmussen <mir at datanom.net> wrote:
> 
> 
> On Tue, 17 Nov 2015 11:01:58 +0100 (CET)
> Alexandre DERUMIER <aderumier at odiso.com> wrote:
> 
> > 
> > I'm thinked to use rrd files to have stats on a long time. (maybe do average
> > on last x minutes)
> > 
> > (for example we don't want to migrate a vm if the host is overload for 1 or
> > 2 minutes,
> > because of a spiky cpu vm)
> > 
> > 
> Is it not the point with this to take care of short time load? Long
> time load should be handled by human intervention.

I thought exactly the opposite. You will get a 'unstable' system
if you react to short time load changes.

See the theory of control systems:

https://en.wikipedia.org/wiki/Control_system

Any electronic engineer can teach you how simple it is to build an oscillator
;-)

Consider that a VM has a highly unpredictable behavior.