Before migrating a virtual machine to Compute Engine, you need to determine which target instance types and sizes to use. Migrate for Compute Engine has a rightsizing feature to help you answer this question. The feature includes built-in usage monitoring and recommends instance types optimized for cost and performance.
Rightsizing provides two types of recommendations:
- Performance-based recommendations: Recommends Compute Engine instances based on the CPU and RAM currently allocated to the on-premises VM. This recommendation is the default.
- Cost-based recommendations: Recommends Compute Engine instances based
- The current CPU and RAM configuration of the on-premises VM.
- The average usage of this VM during a given period. To use this option, you must activate rightsizing monitoring with vSphere for this group of VMs and allow time for Migrate for Compute Engine to analyze usage.
Recommendations are accessible from the vCenter Web Client user interface, PowerShell module, REST API, and Migrate for Compute Engine Waves for mass migration planning.
Suggested options also include expected monthly costs. These are relative cost estimates and not intended for billing forecasts. The cost estimate uses on-demand compute prices with sustained-use discounts only; it doesn't include disk and network cost or consider reduced-cost options.
Rightsizing VMs from vSphere
When you specify which VMs to monitor, the on-premises Migrate for Compute Engine On-Premises Backend virtual appliance starts collecting and analyzing utilization statistics from VMware vSphere. It classifies the activity it observes into patterns based on estimated memory and CPU needs.
For better recommendations, Migrate for Compute Engine recommends monitoring the migrated workloads for at least seven consecutive days (or one typical business week). Migrate for Compute Engine warns you when the monitoring period is insufficient for an adequate recommendation.
Even if the monitoring period is insufficient, Migrate for Compute Engine still offers a cost-optimized recommendation based on the data available.
Rightsizing VMs from AWS
Migrate for Compute Engine also offers rightsizing recommendations for VMs currently hosted on AWS. Unlike rightsizing recommendations for vSphere, recommendations for AWS instances are not based on monitoring of instance usage; they are based upon the CPU and memory configuration of the source instance.