Re: High CPU load, but nothing consuming it...

[Gary Roach <gary719_list1@verizon.net>]

On 02/18/2016 08:43 AM, Florent B wrote:
> On 02/18/2016 05:31 PM, Erick Ocrospoma wrote:
> > Hi,
> >
> > On 18 February 2016 at 10:26, Florent B <florent@coppint.com> wrote:
> > > Hi everyone,
> > >
> > > Today I have a little problem with a server on Jessie.
> > >
> > > It acts as a load balancer with IPVS+Keepalived.
> > >
> > > It is clustered with another server as failover, both servers have the
> > > same problem. Even if one of them is "slave", without charge.
> > >
> > > Sometime CPU load jump over 15 (1min average) and goes down to near zero
> > > a few minutes later. In the meantime, all CPU stats are "normal" (stable
> > > iowait, etc.).
> > >
> > > Here you can see my monitoring graphs for CPU Load :
> > > http://oi65.tinypic.com/kccu9.jpg
> > >
> > > And there for CPU utilization : http://oi66.tinypic.com/2w6sz9s.jpg
> > >
> > > You can see CPU is always idle...
> > >
> > > Both servers are virtualized with kvm last version.
> > >
> > > I have other servers like this, configured the same way, which does not
> > > have the problem.
> > >
> > > Does someone have an idea on how to explain this ?
> > >
> > > Thank you a lot.
> > >
> > > Florent
> > When I/O is high but cpu is not comsumed at all, it could be network
> > who is generating load. Do you have any network graph or stat ?
> Hi and thank you for your answer.
>
> Here are network graphs for the period :
> http://oi67.tinypic.com/macbvp.jpg & http://oi67.tinypic.com/2h7i15j.jpg
>
> Network is not included in I/O ? As you can see there is no extra load
> on network at this specific time...
Try using KsysGuard. I keep it in the bottom right of my screen at all 
times. The process table will tell you which process is soaking up your 
cpu time. This may give you a better chance of finding the problem. You 
could also use ps but KsysGuard is way easier to use.

Gary R.