A node is a single VMware ESXi host that hosts virtual machine desktops in a Horizon 7 deployment.
Horizon 7 is most cost-effective when you maximize the consolidation ratio, which is the number of desktops hosted on an ESXi host. Although many factors affect server selection, if you are optimizing strictly for acquisition price, you must find server configurations that have an appropriate balance of processing power and memory.
There is no substitute for measuring performance under actual, real world scenarios, such as in a pilot, to determine an appropriate consolidation ratio for your environment and hardware configuration. Consolidation ratios can vary significantly, based on usage patterns and environmental factors. Use the following guidelines:
- As a general framework, consider compute capacity in terms of 8 to 10 virtual desktops per CPU core. For information about calculating CPU requirements for each virtual machine, see Estimating CPU Requirements for Virtual Machine Desktops.
- Think of memory capacity in terms of virtual desktop RAM, host RAM, and overcommit ratio. Although you can have between 8 and 10 virtual desktops per CPU core, if virtual desktops have 1GB or more of RAM, you must also carefully consider physical RAM requirements. For information about calculating the amount of RAM required per virtual machine, see Estimating Memory Requirements for Virtual Machine Desktops.
Note that physical RAM costs are not linear and that in some situations, it can be cost-effective to purchase more smaller servers that do not use expensive DIMM chips. In other cases, rack density, storage connectivity, manageability and other considerations can make minimizing the number of servers in a deployment a better choice.
- In Horizon 7, the View Storage Accelerator feature is turned on by default, which allows ESXi 5.5 Update 2 and later hosts to cache common virtual machine disk data. View Storage Accelerator can improve performance and reduce the need for extra storage I/O bandwidth to manage boot storms and anti-virus scanning I/O storms. This feature requires 1GB of RAM per ESXi host.
- Finally, consider cluster requirements and any failover requirements. For more information, see Determining Requirements for High Availability.
For information about specifications of ESXi hosts in vSphere, see the VMware vSphere Configuration Maximums document.