Horizon Connection Server can be installed either on a physical server or in a virtual machine.

Connection Server Configuration Example

This example uses a virtual machine with the specifications listed in Connection Server Virtual Machine Example. The ESXi host for this virtual machine can be part of a VMware HA cluster to guard against physical server failures.

Table 1. Connection Server Virtual Machine Example
Item Example
Operating system See supported operating systems in the Horizon Installation document.
RAM 10GB
Virtual CPU 4
System disk capacity 70GB
Virtual SCSI adapter type Select either LSI Logic SAS or VMware Paravirtual (PVSCSI).

Using PVSCSI may require additional steps depending on the version of Windows to be installed. For more information, see the VMware Knowledge Base article Configuring disks to use VMware Paravirtual SCSI (PVSCSI) controllers (1010398).
Virtual network adapter VMXNET 3
Network adapter 1Gbps NIC

Connection Server Cluster Design Considerations

You can deploy multiple replicated Connection Server instances in a group to support load balancing and high availability. Groups of replicated instances are designed to support clustering within a LAN-connected single-data-center environment.

Important: To use a group of replicated Connection Server instances across a WAN, MAN (metropolitan area network), or other non-LAN, in scenarios where a Horizon deployment needs to span data centers, you must use the Cloud Pod Architecture feature. For more information, see the Administering Cloud Pod Architecture in Horizon document.

Maximum Connections for Connection Server

The VMware Knowledge Base (KB) article https://kb.vmware.com/s/article/2150348 provides information about the tested limits regarding the number of simultaneous connections that a VMware Horizon deployment can accommodate.

PCoIP Secure Gateway connections are required if you use Unified Access Gateway appliances for PCoIP connections from outside the corporate network. Blast Secure Gateway connections are required if you use Unified Access Gateway appliances for Blast Extreme or HTML Access connections from outside the corporate network. Tunneled connections are required if you use Unified Access Gateway appliances for RDP connections from outside the corporate network and for USB and multimedia redirection (MMR) acceleration with a PCoIP or Blast Secure Gateway connection.

Although the Unified Access Gateway appliance can support a maximum of 2,000 simultaneous connections, you might choose to use 2 or 4. The required amount of memory and CPU usage might dictate that you add more Unified Access Gateway appliances per Connection Server instance to spread the load.

Although 5 Connection Server instances (suitably configured) could handle 20,000 connections, you may want to consider using 6 or 7 Connection Servers for availability planning purposes, and to accommodate connections coming from both inside and outside of the corporate network.

For example, if you had 20,000 users, with 16,000 of them inside the corporate network, you would need 5 Connection Server instances inside the corporate network. That way, if one of the instances became unavailable, the 4 remaining instances could handle the load. Similarly, for the 4,000 connections coming from outside the corporate network, you would use 2 Connection Server instances so that if one became unavailable, you would still have one instance left that could handle the load.

These numbers assume that external connections are presented through a gateway. In this example, each of the Connection Server instances handling external connections would be paired with 3 Unified Access Gateway appliances, load balanced across both Connection Server instances, so that if one became unavailable, the 2 remaining appliances could handle the load.

In all cases, users would need to reconnect if they were using a Connection Server or gateway that became unavailable.

Hardware Requirements for Unified Access Gateway with VMware Horizon

VMware recommends to use 2 vCPUs and 4GB RAM for Unified Access Gateway appliances to support maximum number of connections when used with VMware Horizon.
Table 2. Hardware Requirements for Unified Access Gateway
Item Example
Operating system OVA
RAM 4GB
Virtual CPU 2
System disk capacity 20GB (changing the default log level requires additional space)
Virtual SCSI adapter type LSI Logic Parallel (the default for OVA)
Virtual network adapter VMXNET 3
Network adapter 1Gbps NIC
Network Mapping Single NIC option