Auto-scale: Adjusting Machine Size/Density Considerations

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When using auto-scale, you can switch to larger machines with the same density of users to provide cost savings. This includes slightly less compute cost, fewer disks, and less management.

This topic discusses what you must consider when you change the VM size in the auto-scale configuration.

Example: Change VM Size from D4 to D8

When you adjust machine size/density for a host pool, there are many places this change affects. In this example, you keep the same density (1 user per CPU), but move to a larger machine size (D4 to D8). In addition, the host pool needs to regularly accommodate 120 user sessions.

Note: The example shown below moves to a larger machine size (D4 to D8). To move to a smaller machine size (for example, D8 to D4), you follow the same steps.

Current auto-scale settings

The following are the current auto-scale settings:

VM Size: D4as_v5
Session limit per host: 4
Base host pool capacity: 30
Min active host capacity: 2
Burst beyond base capacity: 8 (to accommodate up to 150 users)
Pre-stage Hosts: Hosts to be active by start of work hours: 15

Change the VM size to D8as_v5

If you change to VM Size to D8as_v5 and you want to keep the same user density, you must adjust the following:

Switch the VM Size to D8as_v5.
In Host Pool Properties, change the Session limit per host to 8.

Note: Changing the Session limit per host to 8 increases the Maximum host pool sessions (total capacity) of the pool to 304.
To reduce the Maximum host pool sessions, in Host Pool Sizing, make the following changes:
- Base host pool capacity: 15
- Min active host capacity: 2
- Burst beyond base capacity: 4 (to accommodate up to 150 users)
In Pre-stage Hosts, change Hosts to be active by start of work hours to 8.

Note: This needs to be adjusted because you do not want all the machines in the host pool running at this time. If there are multiple schedules, each schedule needs to be adjusted.