Considerations to downsize the vCenter server compute parameters i.e. CPU/RAM

Products

• VMware vCenter Server

Issue/Introduction

This is applicable in certain scenarios where vCenter is over provisioned and requires CPU/RAM resources to be scaled back down.

Environment

vCenter server 7.x

vCenter server 8.x

Resolution

Steps to downsize vCenter server :

• Take valid backup/snapshot of vCenter server. (If the vCenter servers are in ELM, take offline snapshots of all the vCenter server)
• Login to the ESXi Host hosting the vCenter server VM
• Gracefully shutdown the vCenter server VM
• Modify the cpu/memory as per the requirement. (Select the VM, go to edit settings and make the changes to CPU/Memory )
• Power on the vCenter server.
• Validate all the services started successfully after the changes were made. ( connect to the vCenter server using ssh, run the command "service-control --status" to make sure all the required services are up and running)
• Revert back using the snapshot in case the services do not come up post making the changes.

Additional Information

Note : When downsizing the vCenter Server with less cpu or memory than the minimal supported, though the algorithim will dynamically distribute the available memory to the various resources, it could lead to performance degradation as the different services may not be receiving the amount of memory they require to run.

Hardware reqirement for vCenter server appliance :

Please refer to the Broadcom Document : Hardware requirement for vCenter server appliance