08-04-2011 01:07 AM - edited 03-07-2019 01:32 AM
Hi
I have a pair of Nexus 7000s acting as distribution switches for 52 access layer stacks of 3750x's.
Southbound there are 52 Layer 2 VPCs into each N7K. The N7Ks are a HSRP pair providing L3 gateway functionality for all devices connected to the access layer stacks.
Northbound is Layer 3 Routed using EIGRP.
I was running 5.1.2 on both, I have now upgraded one of them to 5.2.1 but the behaviour is the same.
N7K#show process cpu history
767097676567655666567677666666065706566767666665676764666665675656675767
293035610892288400697302942919049406951470983107411038553524005029828304
100 * * *
90 ** * *
80 *** * * *
70 ******** ** ** *** * ** *** * ***** * * ** * * *** * *
60 ***************************************************** ***** **** *******
50 ************************************************************************
40 ************************************************************************
30 ************************************************************************
20 ########################################################################
10 ########################################################################
0....5....1....1....2....2....3....3....4....4....5....5....6....6....7.
0 5 0 5 0 5 0 5 0 5 0 5 0
CPU% per hour (last 72 hours)
* = maximum CPU% # = average CPU%
I'm concerned about the CPU peaking at 100% and averaging at 20%, seems a bit high to me. Is this normal, or should I open a TAC case?
N7K# show system resources
Load average: 1 minute: 0.05 5 minutes: 0.25 15 minutes: 0.29
Processes : 344 total, 2 running
CPU states : 12.5% user, 15.0% kernel, 72.5% idle
Memory usage: 4109560K total, 1586740K used, 2522820K free
Current memory status: OK
08-04-2011 05:46 AM
Hi,
This high cpu will not give you any problem on your trafic, the 7000 platform as a robust preemptive scheduler and the control and dataplane are seperated.
Depending on what you do, the cpu might be a bit high. High cpu is cause be misbehaving control protocol or excessive trafic to the cpu.
You can start by looking at what process is taking a lot of ressource. Filtering on that process, try capturing cpu bound trafic using the internal Wireshark.
Could be arp, glean, dhcp,fragment....need a sh process cpu sort
08-04-2011 07:44 AM
The periodic CPU spike in the N7K is normal (usually caused by a process called platform). It is because the N7K will perform periodic internal function and this function generate a CPU spike.
HTH,
jerry
08-04-2011 07:45 AM
I'm running an SNMP access list and also have the default COPP strict priority, pretty surprised anything external could push the CPU to 100% with the strict COPP policy applied..
02-27-2013 08:37 PM
We have 2 N7K in a vPC Bundle , the one which is HSRP standby has significate highe cpu , about 40% higher caused by process platform.
Now we are investigating what process platform could make it to consume such hoch cpu load
02-21-2018 08:44 AM
Virtual Port-channel (VPC) is a feature for Nexus-connected L2 networks where a pair of Nexus devices share the data-plane of LACP port-channels while maintaining separated management and control planes. This yields a loop-free L2 trunk connection between access/distro and core layers granting additional non-blocking uplink bandwidth.
Downstream L2 devices communicating with gateway HSRP SVI’s over VPC has never been a problem on Nexus. Static routing and L3 routed P2P have also worked since routing was introduced on Nexus.
Dynamic routing with EIGRP/OSPF/BGP, however, between the VPC-connected Nexus platforms and another device on a L2 VLAN segment requires very careful planning. If not handled properly, a misconfigured Nexus dynamic routing peering will cause network instability.
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