This section provides various general best practices for sizing your deployment.
- User density—If concurrency is a concern, calculate how many users will use the environment at the peak of utilization. For example, if only 80 percent are using the environment at any time, the environment must support only that number of users (plus a failure capacity).
- Disaster recovery—For DR planning, Dell Technologies recommends that you implement a dual or multi-site solution. The goal is to keep the environment online and, in case of an outage, to perform an environment recovery with minimum disruption to the business.
- Management and compute clusters—For small environments, it may be appropriate to use a combined management and compute cluster. For environments deployed at a larger scale, Dell Technologies recommends using separate management and compute layers. When creating a management cluster for a large-scale deployment, consider using the VxRail E560F to reduce the data center footprint. With a more flexible platform that accommodates a wider variety of VDI application workloads, the VxRail V570F is preferred for compute clusters.
- Network isolation—The design shown in this document illustrates a two-NIC configuration per appliance with all the traffic separated logically using VLAN. When designing for larger-scale deployments, consider physically separating the management and VDI traffic from the vSAN traffic for traffic isolation and to improve network performance and scalability.
- FTT—Dell Technologies recommends sizing storage with NumberOfFailuresToTolerate (FTT) set to 1, which means that you must double the amount of total storage to accommodate the mirroring of each VMDK.
- Slack space—Dell Technologies recommends adding an additional 30 percent of slack space to prevent automatic rebalancing of storage, which impacts performance. Automatic balancing occurs when the storage reaches 80 percent of the full threshold. Therefore, we recommend 70 percent to reserve a 10 percent buffer.
- All-flash compared to hybrid:
- Hybrid and all-flash configurations have shown to provide similar performance results when testing VDI configurations. Because hybrid uses spinning drives, consider the durability of the disks.
- Only all-flash configurations offer deduplication and compression for vSAN. Dell Technologies recommends all-flash configurations for simplified data management.
- All-flash configurations need considerably less storage capacity than hybrid configurations to produce similar FTT, as shown in the following table.
Note: Enabling certain data efficiency features can incur processing overhead.
Table 14. FTT comparisons Configuration VM size FTM FTT Overhead Capacity required Hosts required Hybrid 50 GB RAID-1 (Mirrored) 1 2 x 100 GB 3 All-flash 50 GB RAID-5 (3+1) (Erasure coding) 1 1.33 x 66.5 GB 4 Hybrid 50 GB RAID-1 (Mirrored) 2 3 x 150 GB 4 All-flash 50 GB RAID-6 (4+2)(Erasure coding) 2 1.5 x 75 GB 6
Note: For more information about multi-site design considerations for Horizon, see the VMware Workspace ONE and VMware Horizon Reference Architecture.