[Problem Description]
In a N+1 backup scenario, the CPU-usage of backup AC is high.
[Problem Analysis]
1.Run display ap all to check whether all APs are online on the backup AC.
If all APs are online on the backup AC, it is normal that the CPU-usage is high.
2.Run display startup to check current version and patch version.
<AC1>display startup
Configured startup system software: flash:/AirEngine 9700-M_V200R021C00SPC100.cc
Startup system software: flash:/AirEngine 9700-M_V200R021C00SPC100.cc
Next startup system software: flash:/AirEngine 9700-M_V200R021C00SPC100.cc
Startup saved-configuration file: flash:/vrpcfg.zip
Next startup saved-configuration file: flash:/vrpcfg.zip
Startup patch package: flash:/AirEngine 9700-M_V200R021SPH1b0.pat
Next startup patch package: flash:/AirEngine 9700-M_V200R021SPH1b0.patIf the version or patch version is too old, update it.
3.Check the tasks that cause high CPU usage.
[AC-diagnose] display cpu-usage
CPU Usage Stat. Cycle: 30 (Second)
usr: 3.4% sys: 1.1% irq: 0.0% softIrq: 0.0%
CPU Usage: 4.7% Max: 46.7%
CPU Usage Stat. Time : 2019-10-14 10:59:16 (core 0)
CPU Usage Max. Time : 2019-10-14 10:56:43 (core 0)
Core-0 Usage: 4.7% usr: 3.4% sys: 1.1% irq: 0.0% softIrq: 0.0%
Core-1 Usage: 3.7% usr: 2.6% sys: 1.2% irq: 0.0% softIrq: 0.0%
PID ProcessName CPU% Runtime State
188 vos.o 4.7 66380 S
191 wmi 0.6 5990 S
190 wmi 0.6 6035 S
194 nac 0.5 4791 S
195 nac 0.5 4807 S
189 wmc 0.5 4675 S
196 ucm_gc 0.3 3774 S
192 dhcp 0.3 3764 S
......
[AC6605-diagnose] display cpu-usage pid 188 //The corresponding ProcessName is vos.o.
The Thread CPU usage: % of ProcessId: 188
--------------------------------------------------
VosTaskId ThreadID ThreadName CPU% Runtime State
45 441 SessionWorkerTask 54.4 24499 S
54 450 bcmCNTR.0 4.9 3668 S
0 402 vos.o 4.0 2820 R
189 782 ROUT 3.2 2541 S
171 567 POE 2.8 1876 S
57 453 bmLINK.0 2.5 1897 S
3 344 TICK 2.3 1813 S
202 795 STP 1.9 1407 S
169 565 AREM 1.6 1146 S
50 446 bcmINTR 1.5 1131 S
255 1047 We0 1.4 146 S
43 439 WebT 0.9 854 S 4. Check the Check the historical CPU usage.
[AC6605-diagnose] display cpu-usage history
100%|
95%|
90%|
85%|
80%|
75%|
70%|
65%|
60%|
55%|
50%|
45%|
40%|
35%|
30%|
25%|
20%|
15%|
10%|
5%|*************************************************************************************************************************
--------------------------------------------------------------------------------------------------------------------------
60 45 30 15 0
(minutes)5.If the CPU usage is high in the past, check the logs to find the tasks which cause the high CPU-usage
2018-2-24 10:52:34+00:00 AC6605 %%01MON/4/CPU_USAGE_HIGH(l)[50]:The CPU is overloaded, and the top three thread CPU occupancy are TASK1 TASK2 TASK3. (CpuUsage=xx%, Threshold=xx%)[Root Cause]
1.APs are online and CPU-usage is high. It is normal.
2.Some task cause the high CPU-usage
[Solution]
Common tasks that cause high CPU usage and solutions
| Task Name | Description | Cause of High CPU Usage | Solution |
|---|---|---|---|
| DS0/DS1 | Synchronizes data from the NMS. | Synchronization is frequent. | Increase the synchronization interval on the NMS. |
| IC | Information center main task, which receives and outputs the logs, alarms, and debugging information generated by service modules. | Logs and debugging information are frequently triggered. | Reduce the frequency at which operations triggered by logs and debugging information are performed. |
| PM/PMS | Performance management task, which processes performance statistics data and PM configuration commands as well as reports performance statistics. | When there are many PM configurations (a large amount of statistics data), performance data collection and processing are triggered. |
|
|
We0/We1 …WebT/ SessionAdminTask /SessionWorkerTask |
Web service processing task, which processes requests of all web users. | Operations are frequently performed on the web platform. | Reduce the frequency at which operations on the web platform are performed. |
| WMT_PM | Is used by eSight to collect PM performance data. | eSight periodically collects AP data. | Adjust the PM performance measurement interval. |
| _S0fSNMP/SNP6 | Processes operations of IPv4/IPv6 SNMP NMSs. | A large number of SNMP NMSs are connected, or operations on SNMP NMSs are performed frequently. | Reduce the frequency at which operations on SNMP NMSs are performed. |
| WMT_WPM | Processes the performance statistics reported by APs. | A large amount of performance data is collected after the device is enabled to report performance statistics to eSight. | Adjust the PM performance measurement interval. |
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