Hi sarahr202,
Performance Mode: Enables vMX to run in performance mode. Performance mode needs more CPUs (check below for specifications ) and memory to run at a higher bandwidth. When you enable performance mode, make sure you have configured the proper number of vCPUs and memory for your VMs based on your use case. If you have not configured enough vCPUs, vMX runs in lite mode.
Lite Mode: Enables vMX to run in lite mode and disables performance mode. Lite mode needs fewer CPUs( check below for specifications ) and memory to run at lower bandwidth.
While the bandwidth varies upon how you deploy and what resources you use, there are a few things you might need to be mindful of while choosing between the modes:
1) Due to a DPDK version change in Junos OS Release 18.1R1 and later, ESXi 6.5 is the minimum version required to run the vMX router if you are operating in high-bandwidth mode (performance mode). If you are operating the vMX router in low-bandwidth (lite) mode, you can use ESXi 6.0 or ESXi 5.5.
NOTE: For performance mode, the minimum software requirement for ESXI 6.5 is Junos OS Release 18.1R1 and later.
2) If you are running virtio interfaces in lite mode, you can use up to 96 ports. Other configurations running in performance mode support up to 23 ports.
3) Starting in Junos OS Release 15.1F6 and later releases performance mode is enabled implicitly by default.
When you enable performance mode, make sure you have configured the proper number of vCPUs (four or more VPCUs) and memory for your VMs based on your use case.
4) You can explicitly enable lite-mode. If you are using paravirtualized network interfaces such as virtio (for
KVM) or VMXNET3 (for VMware) for lab simulation use cases, you can disable performance mode by
including the lite-mode statement.
More details below:
https://www.juniper.net/documentation/en_US/vmx/information-products/pathway-pages/getting-started/vmx-gsg-vmware.pdf
Hope this helps 🙂
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