Wired Intelligent Edge

Hi,

Over night some of our switches increesed their CPU usage from 5-10% to 50-70% and have staid there for a few days. It is 5 swtiches and they all started increese at the exact same time.

There is no increse in trafficflow, There was no change (this happnend on the night sun-mon). 
I have looked in the logs, cant se anything. 
I have investigated a possible loop but not able to find anything.

Spanning-tree is enabled on all switches.

Not sure where to look now, anyone have ideas on where to start?

Start with checking show logging -r CLI command's output so you will be able to infer if there is any logs on the relevant issues' timeframe and infer about any possible relationship.

Thanks for your suggestion.
The problem has been resolved. 

I had some work to do on one of the switches in the network (this switch did not have High CPU-load). So i disconnected it from the network, for a few minutes, triggering a STP-topology change. This somehow fixed the issue. Looking into my monitoring software, the CPU drops to normal at the exact moment I lost my first ping to the switch I was working on.

The high CPU-load dropped on all switched involved with this issue.... Not sure why and how but the issue is gone.