Virtualizing session hosts, whether through Remote Desktop Services or Azure Virtual Desktop, demands careful consideration of virtual machine (VM) configurations to match diverse workload requirements. These guidelines serve as a starting point for performance estimation. To ensure an optimal user experience, continuous monitoring and adjustments based on actual usage are crucial. Flexibility in scaling deployments up or down in Azure allows for fine-tuning resources as needed.
Understanding Workload Types for Terminal Server Capacity Planning
Users engage with session host VMs for a variety of tasks, each placing different demands on system resources. Categorizing these workloads is essential for effective VM sizing and capacity planning, which can be streamlined with a Terminal Server Calculator approach. The table below outlines common workload types, representative users, and example applications to guide your initial sizing estimations. Remember, post-deployment monitoring and adjustments are vital for optimal performance.
| Workload type | Example users | Example apps |
|---|---|---|
| Light | Data Entry Clerks | Database entry applications, command-line interfaces |
| Medium | Consultants, Market Researchers | Database entry applications, command-line interfaces, Microsoft Word, static web pages |
| Heavy | Software Engineers, Content Creators | Database entry applications, command-line interfaces, Microsoft Word, static web pages, Microsoft Outlook, Microsoft PowerPoint, dynamic web pages, software development tools |
| Power | Graphic Designers, 3D Model Makers, Machine Learning Researchers | Database entry applications, command-line interfaces, Microsoft Word, static web pages, Microsoft Outlook, Microsoft PowerPoint, dynamic web pages, photo and video editing software, Computer-Aided Design (CAD), Computer-Aided Manufacturing (CAM) |
Example of different workload types for virtual machines.
Single-Session VM Sizing: Calculating Resources Per User
In single-session scenarios, where each session host VM accommodates only one user at a time (common in Azure Virtual Desktop personal host pools), VM sizing should mirror physical device guidelines. A terminal server calculator for single-session VMs would primarily focus on the resource needs of individual power users. It’s generally recommended to start with a minimum of two physical CPU cores per VM, often translating to four vCPUs with hyper-threading. For precise sizing, consulting software vendors regarding specific application requirements is advisable.
The following table provides minimum specifications for different workload types in single-session environments, offering a foundational dataset for a terminal server calculator focused on individual user needs.
| Workload type | vCPU/RAM/OS storage minimum | Example Azure instances | Profile container storage minimum |
|---|---|---|---|
| Light | 2 vCPUs, 8-GB RAM, 32-GB storage | D2s_v5, D2s_v4 | 30 GB |
| Medium | 4 vCPUs, 16-GB RAM, 32-GB storage | D4s_v5, D4s_v4 | 30 GB |
| Heavy | 8 vCPUs, 32-GB RAM, 32-GB storage | D8s_v5, D8s_v4 | 30 GB |
Recommended virtual machine sizes for single-session workloads.
Multi-Session VM Sizing: Optimizing Resource Density with a Terminal Server Calculator
Multi-session environments, where multiple users share a single session host VM (like Azure Virtual Desktop pooled host pools with Windows 11 Enterprise multi-session), necessitate a different sizing strategy. A terminal server calculator for multi-session deployments shifts focus to maximizing user density per VM while maintaining acceptable performance.
The table below suggests maximum user density per vCPU and minimum VM configurations for varying workloads in multi-session scenarios. These figures offer crucial inputs for a terminal server calculator designed to balance cost-efficiency and user experience. Again, for application-specific guidance, vendor consultations are recommended.
| Workload type | Maximum users per vCPU | Minimum vCPU/RAM/OS storage | Example Azure instances | Minimum profile storage |
|---|---|---|---|---|
| Light | 6 | 8 vCPUs, 16-GB RAM, 32-GB storage | D8s_v5, D8s_v4, F8s_v2, D8as_v4, D16s_v5, D16s_v4, F16s_v2, D16as_v4 | 30 GB |
| Medium | 4 | 8 vCPUs, 16-GB RAM, 32-GB storage | D8s_v5, D8s_v4, F8s_v2, D8as_v4, D16s_v5, D16s_v4, F16s_v2, D16as_v4 | 30 GB |
| Heavy | 2 | 8 vCPUs, 16-GB RAM, 32-GB storage | D8s_v5, D8s_v4, F8s_v2, D8as_v4, D16s_v5, D16s_v4, F16s_v2, D16as_v4 | 30 GB |
| Power | 1 | 6 vCPUs, 56-GB RAM, 340-GB storage | D16ds_v5, D16s_v4, D16as_v4, NV6, NV16as_v4 | 30 GB |
Virtual machine sizing guidelines for multi-session workloads to optimize user density.
For multi-session deployments, it is advisable to limit VM sizes to between 4 and 24 vCPUs. This recommendation stems from the balance between core count and system overhead. VMs with fewer than four cores can lead to UI instability due to Windows’ reliance on parallel threads for rendering, particularly under multi-user load. Conversely, VMs exceeding 32 cores often experience diminishing returns, with synchronization overhead negating the benefits of increased cores. In scenarios with a large number of users, deploying multiple smaller VMs generally outperforms fewer, larger VMs, enhancing both user experience and management flexibility.
Leveraging a Terminal Server Calculator for Efficient VM Sizing
A terminal server calculator is a valuable tool for simplifying the VM sizing process. By inputting key parameters such as:
- Workload Type: Selecting from categories like Light, Medium, Heavy, or Power.
- Number of Users: Specifying the anticipated number of concurrent users.
- Session Type: Choosing between single-session or multi-session deployment.
- Application Profiles: Defining the resource demands of the applications users will utilize.
Such a calculator can provide estimated VM configurations, including vCPU, RAM, and storage recommendations, tailored to specific needs. While the tables provided offer manual guidelines, a terminal server calculator automates these calculations, making capacity planning more efficient and less prone to error. It can also factor in cost considerations, helping optimize resource allocation and Azure spending.
General Virtual Machine Recommendations for Session Hosts
For production workloads in Azure, Premium SSD storage is essential to meet Service Level Agreements (SLAs) and ensure consistent performance. Refer to Service Level Agreements (SLA) for Online Services for detailed information.
Graphics Processing Units (GPUs) significantly enhance the performance of graphics-intensive applications like video editing, 3D modeling, and simulations. Azure offers various GPU-optimized VM sizes and deployment options. Explore GPU optimized virtual machine sizes for more details. For broader information on GPU acceleration in Remote Desktop Services, consult Remote Desktop Services – GPU acceleration.
B-series burstable VMs in Azure are a cost-effective choice for workloads with fluctuating CPU demands. For comprehensive specifications and pricing details, see Sizes for Windows virtual machines in Azure and Virtual Machine series.
Validate Sizing with Workload Testing and Simulation
Ultimately, validating your VM sizing through rigorous testing is crucial. Employ simulation tools to conduct both stress tests and real-world usage simulations. This ensures your system remains responsive and resilient under varying load conditions, meeting user expectations and preventing performance bottlenecks. Remember to simulate peak usage scenarios to proactively identify and address potential scalability issues.
By combining these guidelines with a practical terminal server calculator approach and thorough testing, you can effectively optimize session host VM sizing, ensuring a balance of performance, user experience, and cost efficiency for your virtualized environment.
