The value shown for CPU and memory usage on the performance tab in OneClick does not reflect the real time values of these devices.
How is this calculated?
Typically vendors may supply various values for CPU and memory usage and Spectrum will use one of them to plot the graph on the performance tab.
e.g. Juniper provides the following information how to monitor CPU utilization (in percentage) on the firewall via SNMP.
To monitor CPU utilization (in percentage), the following OIDs can be used:
.22.214.171.124.4.1.3126.96.36.199.0 Average System CPU utilization in percentage.
.188.8.131.52.4.1.3184.108.40.206.0 Last one minute CPU utilization in percentage.
.220.127.116.11.4.1.318.104.22.168.0 Last Five minute CPU utilization in percentage.
.22.214.171.124.4.1.3126.96.36.199.0 Last Fifteen minute CPU utilization in percentage.
In the this situation Spectrum has 4 different values to choose from, as can be seen from the attributes tab below. We can filter by CPU or use the above OIDs if the OID prefix column is visible. The vendor attributes begin with NsResCPU and the internal CA normalised attributes begin with NRM_CPU.
The NRM_CPUIntelPref shows a value of redirection.
NRM_CPUUtilAttr showed a value of 0x49b0147 corresponding to NsResCpuLast5Min so the value displayed by Spectrum is the average value over 5 minutes.
Can we change this value?
To change the value displayed by Spectrum, we can double click on NRM_CPUUtilAttr and it to point to another attribute value.
e.g changing the value of NRM_CPUUtilAttr to 0x49b0146 will display the CPU usage over the last minute.