High CPU load, but nothing consuming it...

[Florent B <florent@coppint.com>]

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