Strange CPU utilization

[Zar Ni Lay Thwin]

Hi All,

           I am seeing odd CPU utilization on Cisco switches.

The thing is when no body login to switch the CPU utilizationis around 55 - 58 %. ( Result from monitoring chart and when I login and check CPU, I can see the five min is around 57%)

As soon as I login to switch CPU utilization starts going down and reach to 8% slowly.  This is huge difference.

Could someone explain why does this thing happen?

[Leo Laohoo]

What IOS version?

[Zar Ni Lay Thwin]

Hi Leo

Its 12.2(55)EX2

[Leo Laohoo]

What appliance is this? 

When you are doing your monitoring, is it via SNMP?

[Zar Ni Lay Thwin]

Yeah it is via SNMP v2c. Its Cisco Prime Infrastructure 2.0

[Leo Laohoo]

What is the model of the appliance running 12.2(55)EX2?

[Zar Ni Lay Thwin]

Hi Leo , they are 3560 Switches.

[Leo Laohoo]

Hi Leo , they are 3560 Switches.

Stop playing games. 

Standard 3560 (24- or 48-port) will not run EX2. 

EXn-series IOS is an INTERRIM IOS.  It is primarily designed to get your switch working and for you to upgrade the IOS.

I would recommend you upgrade to 15.0(2)SE4.  Don't even consider upgrading to any of the version as you'll encounter more trouble.

[Zar Ni Lay Thwin]

Hi Leo,

           Upgraded to 15.2(1)E1 which is latest.

High CPU is gone after upgrading to this version but now Memory is very high again.

See the attached screenshot.

Cheers

Zarni

[Leo Laohoo]

Upgraded to 15.2(1)E1 which is latest.
High CPU is gone after upgrading to this version but now Memory is very high again.

Zarni,

Read all of my posts in this thread.  I have never recommended this IOS version, 15.2(1)E1.  I will NEVER recommend anyone use 15.2(1)E or 15.2(1)E1 because I know there are CPU and memory issues with this version.  

[Zar Ni Lay Thwin]

12.2(55)EX3  resolved my issue mate.

For some reason ( Service Discovery Gateway ), I need to use 15.2 on others 3560s ( 48 Port proper switches ).

Cheers!

[Leo Laohoo]

For some reason ( Service Discovery Gateway ), I need to use 15.2 on others 3560s ( 48 Port proper switches ).

I doubt it.  There is no IOS verson 15.2 for plain 3560/3560G.

[Zar Ni Lay Thwin]

Hi Leo,

           Thanks for reminding me.

Ya I forgot to mention that they are 3560X.

Cheers

Zarni

[Haihua Rong · Accepted solution]

Hello,

You may be hitting the next bug:

High CPU when no Console/VTY activity

CSCth24278

The bug is fixed in 12.2(58)SE1 and 12.2(55)SE3, or later releases.

Link

------

https://tools.cisco.com/bugsearch/bug/CSCth24278

Haihua