Once design decisions are approved, you will move on to creating a logical design for the infrastructure, including compute, storage, networking, operations, and other additional components of your design. Your logical design must follow the design decisions.
For example, let’s map the following design decisions to the logical design.
The design will require two separate SDDCs:
- Standard SDDC with 99.9% availability
- Stretched cluster SDDC with 99.99% availability
To properly accommodate this requirement, your logical design should include the following:
- The number of hosts and host types per SDDC
- The number of vSphere clusters
- Desired AWS Region and AZs for the deployment
- AWS account and connected VPC
- Network connection between SDDCs
- SDDC group
- vTGW and DXGW
- Recommendation for workload placement
- eDRS policies configuration
- Storage policies configuration
- VMware Aria Operations for Logs alerts and dashboards
- VMware Aria Operations custom dashboards
When creating a logical design, you will map the design decisions on the current product’s capabilities. In some cases, it would not be possible to satisfy a design decision, because of product interoperability or known bugs. All changes must be properly documented, and design decisions should be updated and communicated to the project stakeholders. Do not move on without getting all the required approvals; it may affect the product implementation later!
Upon completion, the logical design must be presented to the relevant technical teams, with the feedback captured and incorporated into the design.
Logical design is a foundation for a physical design. The physical design depicts the necessary configuration information, including the following:
- Management subnet CIDR for both SDDCs
- Workload segments CIDRs
- eDRS policy thresholds
- Custom storage policy thresholds
- BGP configuration, including ASN, peer-to-peer network CIDR, VLAN, and so on
- HCX Service Mesh and Uplinks configuration
The main goal of the physical design is to ensure necessary configuration information is available for the implementation and configuration workbooks. Even at this stage, you may encounter additional risks that were not captured before. It’s very common to see a lack of available VLANs, BGP limitations, and so on. Some of them may affect your design decision and may require revisiting the logical design.