Performance Problem with Cisco 2960S ?

Answered Question
Feb 9th, 2011
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We have seen high CPU utilization on some Cisco switches of type 2960S. Also we got info, that applications are running with poor performance or with interuption. Is this a know problem?

Following IOS is loaded: C2960s-universalk9-mz.122.55.SE

Correct Answer by Shashank Singh about 6 years 4 months ago

Hi,


High CPU on this platform and IOS can be a cosmetic issue due to the bug CSCth24278. Details are present at:

http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCth24278


Switch incorrectly reports high CPU when no console/telnet session is active to the switch.


Please telnet into the switch and check out the outputs of "show proc cpu hist" and see if CPU utilization drops.If you are hitting this bug, there will not be any performance impact due to this bug as the CPU is not actually high.


Cheers,

Shashank


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Correct Answer
Shashank Singh Wed, 02/09/2011 - 03:51
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Hi,


High CPU on this platform and IOS can be a cosmetic issue due to the bug CSCth24278. Details are present at:

http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCth24278


Switch incorrectly reports high CPU when no console/telnet session is active to the switch.


Please telnet into the switch and check out the outputs of "show proc cpu hist" and see if CPU utilization drops.If you are hitting this bug, there will not be any performance impact due to this bug as the CPU is not actually high.


Cheers,

Shashank


Please rate if you found the content useful

Latchum Naidu Wed, 02/09/2011 - 07:01
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Hi,


Do you have any STP instances?


Because when the logging event-spanning-tree interface configuration command is configured and logging to the console is enabled, a topology change might generate a large number of logging messages, causing high CPU utilization. CPU utilization can increase with the number of spanning-tree instances and the number of interfaces configured with the logging event-spanning-tree interface configuration command. This condition adversely affects how the switch operates and could cause problems such as STP convergence delay.


High CPU utilization can also occur with other conditions, such as when debug messages are logged at a high rate to the console.

Use one of these workarounds:

–Disable logging to the console.
–Rate-limit logging messages to the console.
–Remove the logging event spanning-tree interface configuration command from the interfaces. (CSCsg91027)


See the below link for more information.
http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_53_se/release/notes/OL22233.html


Please rate the helpfull posts.

Regards,
Naidu.

NetWorkkss Thu, 01/26/2012 - 07:36
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Hello,


I have a same problem but I don't have an access for the bug toolkit.


Can anyone provide me the contents of the bug CSCth24278 with the solution for to solve the problem ?


Thanks you for help.

Leo Laohoo Thu, 01/26/2012 - 13:40
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What is the IOS you are running?

NetWorkkss Fri, 01/27/2012 - 05:46
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Hello,


C2960S Software (C2960S-UNIVERSALK9-M), Version 12.2(55)SE2


Thanks you

Leo Laohoo Fri, 01/27/2012 - 14:45
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C2960S Software (C2960S-UNIVERSALK9-M), Version 12.2(55)SE2

Ok, try either the following:


1.  12.2(55)SE4; or

2.  15.0(1)SE2

NetWorkkss Mon, 01/30/2012 - 02:17
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Hello,


The IOS upgrading (12.2(55)SE4 is the only solution ?


Thanks you

Leo Laohoo Mon, 01/30/2012 - 03:36
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The IOS upgrading (12.2(55)SE4 is the only solution ?

There's a reason why the 12.2(55)SE has a number or "re-builds".

butchy1978 Sat, 03/03/2012 - 23:47
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Hi there,

I have noticed high cpu whenever there is no user logged in CLI (12.55SE). This doesn't seemed to affect the real performance though. However after upgrading to 12.2.58SE CPU Utilization is between 8-20%. I think that this high cpu utilization was not present on 2960, only on 2960s but I am not sure though.

Upgrading to 12.2.58SE will most likely solve your problem.

Good luck.

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