High CPU when copying IOS via. FTP

[Mahesh Gohil]

Hi experts,

I am having few GSR Routers and I am pushing a new IOS to be copied on disk systems.

But when process starts CPU reaches to 99% and the in output it shows virtual-exec process eating the CPU.

One way to bring it down is via. clearing vty session but it will end my copying of IOS.
I just want to know why copying of IOS via.FTP from my PC increases the cpu process. and is there any workaround to bring it down with continuing copying operation

Regards
Mahesh

[Mahesh Gohil]

Hello experts,

Any update on this

Regards

Mahesh

[Richard Burts]

Mahesh

I do not have a GSR router to verify this, but the logical explanation is that the router CPU must process each and every one of the FTP packets. When the router is forwarding packets from some external source to some external destination then IOS can do things to forward at high rate with low CPU (since the CPU is not directly involved in forwarding packets). But when the router is the source or the destination of the packet then the packet must be handled by the CPU.

Is the high CPU causing problems or is it just something that you noticed?

HTH

Rick

[Mahesh Gohil]

Hi Rick,

Thanks for your reply. Well it is not causing any problem, I just noticed same but high cpu is always alarming

Just trying to find out some ways to decrease the same

Regards

Mahesh

[Ganesh Hariharan]

Hi Rick,
Thanks for your reply. Well it is not causing any problem, I just noticed same but high cpu is always alarming
Just trying to find out some ways to decrease the same
Regards
Mahesh

Hi Mahesh,

Check out the below link for some explanation on How Can the Exec and Virtual Exec Processes Cause High CPU Utilization?

http://www.cisco.com/en/US/products/hw/routers/ps359/products_tech_note09186a00801c2ae4.shtml#how

Hope to Help !!

Ganesh.H

[Chad Peterson]

Hi Manhesh,

I don't have a GSR to work with at the moment, but I also imagine you could implement CoPP to rate limit how much traffic you push to the CPU from FTP.  You could police it down to a lower rate to prevent your CPU from going high.