[c-nsp] high CPU usage when coyping to flash

[Mark Tinka]

On Sunday, February 26, 2012 05:14:04 PM Alan Buxey wrote:

> its not just your 4900 device - somethings gone a little
> wierd in cisco land since around the introduction of
> 3750 or 2960 devices too - as doing an eg 'archive
> download-sw ....' command kills the switch performance
> for end user connected devices... this never used to be
> the case with eg the 2950, 2970 or 3550 devices - we
> could install new IOS firmware at any time and then
> reload out of hours...we now have to upload the firmware
> out of hours too  :-|

We're seeing the same on the ME3600X as well, as upgrades 
are now done using the 'archive download-sw' command.

It effectively redirects a good portion of the router's 
management/control plane to the upgrade. Any pings to the 
device will show a very high latency, e.t.c., leading to 
various failures in the control plane depending on how 
powerful the CPU is.

The CPU in the ME3600X is pretty solid, so we don't see as 
many routing protocol failures as one would expect, but the 
router is effectively too busy for much else.

Anyway, as these upgrades are occurring within a maintenance 
window, it's all good. Moreover, it would be wise to set the 
Overload Bit (and its equivalent in OSPF) before you start, 
assuming your box is a Layer 3 device.

Mark.
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