This article provides details about high CPU utilization observed on VMware when using vSRX.
High CPU usage for vSRX instances can be observed in the vSphere client under the Performance tab (Monitoring > Performance). The graph below shows CPU usage at approximately 80% for a vSRX device that is completely idle.
This is expected behavior because vSRX operates in a polling model, which can result in high CPU usage on vSphere. The high CPU usage observed on vSphere is due to the way we allocate CPU resources at the hypervisor level and manage them within Junos. It does not reflect the actual CPU usage of the vSRX.
To determine the actual CPU usage of the vSRX, log in to the vSRX and run the following commands:
- show chassis routing-engine - show security monitoring
As shown in the output below, the vSRX CPU usage is approximately 5%, not the 80% reported by vSphere.
root@vSRX1> show chassis routing-engine Routing Engine status: Total memory 8136 MB Max 6021 MB used ( 74 percent) Control plane memory 1992 MB Max 1355 MB used ( 68 percent) Data plane memory 6144 MB Max 4669 MB used ( 76 percent) 5 sec CPU utilization: User 1 percent Background 0 percent Kernel 1 percent Interrupt 0 percent Idle 99 percent Model VSRX RE Start time 2024-08-29 19:51:41 UTC Uptime 16 days, 3 hours, 25 minutes, 28 seconds Last reboot reason Router rebooted after a normal shutdown. Load averages: 1 minute 5 minute 15 minute 3.40 3.39 3.32 root@vSRX1> show security monitoring Flow session Flow session CP session CP session FPC PIC CPU Mem current maximum current maximum 0 0 0 77 82 2097152 N/A N/A