Installing a new greenfield environment without migrating any existing workloads is a valid and time saving technique. Migrations can be complex leading to lengthy projects that need to be planned accordingly.
Perform a detailed analysis of the migration candidates at both a business and technical level to work out the possible migration candidates. At a high level, a business might have the requirement that all workloads should be running on an infrastructure that is compliant with VMware Validated Designs. However, under certain conditions, you might need to make a decision on an application-to-application or VM-to-VM basis for each candidate. Any change in existing workloads, such as changing the platform or migrating, carries potential effects that might not be offset by the re-hosting benefits. Leaving applications and VMs in their existing locations and building adjacent infrastructure to host new workloads might be the best solution in some circumstances.
Understanding the management component, workload application, VM or groups of VMs from a performance, availability and maintenance tolerance is important when choosing a migration method. This assists with planning of the migration including timing and dependencies. The requirements vary for each, and you must also consider infrastructure-wide requirements. Document all requirements and match them to a specific migration option.
Duration and Maintenance Windows
Align duration and maintenance windows to migration process planning. If you deploy a new SDDC environment without migrating any workloads, you do not have to align to any specific timing schedule.
Risk is minimal when you do not change any workload by migrating it to a new environment.
Consider also the risk associated with not migrating a workload, for example, when the existing workloads are hosted on aging or unstable infrastructure.
The existing management components, applications and VMs have a large set of associated metadata. When migrating workloads between environments, this metadata might or might not be needed according to the business and technical requirements. In the non-migration, greenfield, approach, all metadata is retained at the source.
Backup and Rollback
When you select to leave existing workloads in their current environment, there is no need to change the existing backup, restore or rollback methodology. For information about the new considerations for the new validated SDDC environment, see the VMware Validated Design operations documentation.
The process of finalizing an existing environment is different according to the environment. You consider the size, location, criticality and data retention policies. When choosing not to migrate existing workloads to a new validated SDDC environment, the existing environment typically hosts the existing workloads for a more extended time period, until the last application is no longer needed, or a migration project is established and completed.