Pool session distribution in Horizon Cloud seeks to ensure consistent performance and resource efficiency. You can optimize cost, performance, or a combination of cost and performance.
When a pool group includes only one pool, Horizon Cloud selects a healthy virtual machine (VM) with available sessions to allocate. When a pool group includes multiple pools, Horizon Cloud chooses one of the available pools at random to allocate a session to. If that pool has no availability, allocation attempts are made to another pool within the pool group.
Note: VMs undergoing maintenance, including upgrades or operational adjustments, are excluded from session allocation until their maintenance status clears.
Within each pool, VMs are prioritized based on factors such as the following:
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Free sessions: VMs with fewer than the configured threshold percentage for session occupancy are prioritized.
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Session activity: VMs that have recently served fewer sessions in the last few seconds are given priority.
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Load balancer settings: VMs within a configurable load index threshold receive priority. This setting only applies to multi-session pool groups.
Session allocation aligns with Auto Scaling and power management, so user sessions are efficiently distributed across powered-on virtual machines (VMs), minimizing the need to power on VMs that remain unused. When used with the power management settings in the Horizon Cloud multi-session pool group, administrators can set thresholds for session allocation, such as maximum sessions per VM, to prevent overloading any single VM.
New user sessions are first allocated to fill powered-on VMs to the power management threshold, based on their occupancy and load index. This ensures effective VM utilization and power management. Once all VMs are filled to the threshold, the sessions are distributed evenly to spread the load. Refer to Managing Power Options for Pools and Pool Groups for more information.
This workload balance is achieved by the service continually evaluating the load on each powered-on VM. Session allocation processes comply with your security protocols to protect user data and maintain privacy. Using this power management functionality, the system allocates sessions to powered-on VMs based on the administrator's defined distribution logic and current VM loads.
When creating Pool Groups, refer to Create a Single-Session Pool Group, and/or Create a Multi-Session Pool Group for more information.
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