Hello community,
We have a switch stack with 2 x WS-C3850-48T that is hitting high CPU usage. This is causing processes like SNMP and SSH to freeze up and not work properly. ICMP is also being returned with spikes up to 1000ms. Traffic across the switch is stable at this time but we are concerned about this issue. We are running OSPF and L2 MST network off this stack and it is an important part of the network.
Below is the processor output and we see that VMATM Callback is taking up the vast majority of the processor capacity. I understand this can be caused by ports flapping although to my knowledge I do not see this to be an issue on the device.
#sh proc cpu sort | ex 0.00
CPU utilization for five seconds: 88%/17%; one minute: 87%; five minutes: 87%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
180 389994225 13577472 28723 49.41% 41.26% 37.29% 0 VMATM Callback
230 113046002 1378102 82031 11.91% 12.85% 12.66% 0 Spanning Tree
119 27810309 38529865 721 2.33% 2.08% 2.40% 0 IOSXE-RP Punt Se
93 10157266 14009662 725 1.20% 1.08% 0.98% 0 cpf_process_tpQ
160 12155925 10184153 1193 0.88% 1.42% 1.39% 0 MATM RP Shim Pro
547 61551608 12144787 5068 0.88% 2.15% 4.94% 0 SNMP ENGINE
73 7853198 12432391 631 0.72% 0.83% 0.85% 0 IOSD ipc task
212 7890216 15651493 504 0.72% 0.75% 0.77% 0 IP Input
The only error in the logs of recent time is a few of these per day.
Jul 31 22:25:19.225: NTP Core (NOTICE): ntp_receive: dropping message: MODE_PRIVATE restriction.
Jul 31 23:11:46.730: NTP Core (NOTICE): ntp_receive: dropping message: MODE_PRIVATE restriction.
Jul 31 23:16:00.181: NTP Core (NOTICE): ntp_receive: dropping message: MODE_PRIVATE restriction.
Jul 31 23:34:27.774: NTP Core (NOTICE): ntp_receive: dropping message: MODE_PRIVATE restriction.
Aug 1 00:32:14.832: NTP Core (NOTICE): ntp_receive: dropping message: MODE_PRIVATE restriction.
Aug 1 00:45:36.616: NTP Core (NOTICE): ntp_receive: dropping message: MODE_PRIVATE restriction.
