For graphics-intensive desktop deployments, we recommend the VDI-optimized 2U servers that support GPU hardware.

The vSAN Ready Node R7525 can be configured with or without GPUs. Dell Technologies also offers similar configurations in a 1U/1 node appliance, although fewer graphics configurations are available on these platforms.

We have designated common configurations as Management-Optimized, Density-Optimized, and Virtual Workstation. These designations are outlined in the following table and are referenced throughout the document.

vSAN is available in hybrid or all-flash configurations.

After vSAN is enabled on a cluster, all disk devices that are presented to the hosts are pooled together to create a shared data store that is accessible by all hosts in the VMware vSAN cluster. VMs can then be created with storage policies assigned to them. The storage policy dictates availability, performance, and available capacity.

vSAN provides the following configuration options:

• All-flash configuration—Uses flash for both the cache tier and capacity tier to deliver enterprise performance and a resilient storage platform. In this configuration, the cache tier is fully dedicated to writes, allowing all reads to come directly from the capacity tier. This model allows the cache device to protect the endurance of the capacity tier. All-flash configured solutions enable data deduplication features to extend the capacity tier.
• Hybrid configuration—Uses flash-based devices for the cache tier and magnetic disks for the capacity tier. Hybrid configurations are ideal for clients looking for higher volume in the capacity tier. The performance of SSD and magnetic spinning disks is comparable in VDI applications if sufficient magnetic spinning disks are used.

NVIDIA vGPU brings the full benefit of NVIDIA hardware-accelerated graphics to virtualized solutions. This technology provides exceptional graphics performance for virtual desktops and virtual workstations when multiple users share a GPU, as shown in the following figure:

NVIDIA vGPU is the industry's most advanced technology for sharing or aggregating true GPU hardware acceleration between multiple virtual desktops without compromising the graphics experience.

NVIDIA vGPU offers four software variants to enable graphics for different virtualization techniques:

• NVIDIA Virtual Applications (vApps)—Designed to deliver graphics accelerated applications using RDSH
• NVIDIA Virtual PC (vPC)—Designed to provide full virtual desktops with dual 4K monitor support
• NVIDIA RTX Virtual Workstation (vWS)—Designed to provide workstation-grade performance in a virtual environment with support for quad 4K monitors
• NVIDIA Virtual Compute Server (vCS)—Designed to accelerate compute-intensive workloads, such as artificial intelligence (AI), deep learning (DL), and data science run in a virtual machine.

Configure Dell Technologies VDI Solutions with the following NVIDIA GPUs for an optimum user experience that is hosted from your data center:

• NVIDIA M10 (Maxwell)—NVIDIA M10 GPUs are recommended for virtual applications or virtual PC environments. Each card is equipped with 32 GB of video buffer with a maximum available buffer per user of 8 GB. Dell Technologies recommends hosting a maximum of 32 Windows 10 users per card. A maximum of 3 cards are possible but consider sizing with a maximum of 2 cards per node. Configure systems with less than 1 TB of memory when using the M10.
• NVIDIA T4 Tensor Core GPU (Turing)—NVIDIA's Turing architecture is available in the T4 GPU, which is considered the universal GPU for data center workflows. Add up to five GPU cards into each vSAN Ready Node R7525 with an NVMe cache tier and six GPU cards with a SAS cache tier to enable up 96 GB of video buffer. For modernized data centers, use this card in off-peak hours to perform your inferencing workloads.
  Note: On VMware ESXi 7.0U1 and 7.0U2, VMware recommends using high-endurance storage devices for the ESXi OS. Dell Technologies recommends using a BOSS-S1 card in this configuration. However, this will reduce the number of supported NVIDIA T4 GPUs from six to five.
  
  
• NVIDIA A40 (Ampere)—NVIDIA A40 GPUs provide a leap in performance and multi-workload capabilities for the data center, combining superior professional graphics with powerful compute and AI acceleration to meet today’s design, creative, and scientific challenges. Driving the next generation of virtual workstations and server-based workloads, NVIDIA A40 includes features for ray-traced rendering, simulation, virtual production, and more to professionals any time, anywhere.

As a best practice, ensure that members of a cluster that is based on VMware vSAN are identical or as homogeneous as possible in terms of hardware, software, and firmware. This practice is primarily to reduce operational complexity and maintenance requirements. With NVIDIA vGPU and the associated NVIDIA GPUs in a vSAN Ready Node environment, a mixed GPU environment may be necessary or beneficial for several reasons, including:

• Usage patterns and workloads that are better matched to different physical GPU types must be addressed.
• A newer generation of NVIDIA GPUs that adds greater value to the overall solution has been released.
• A previously deployed cluster has GPUs that have reached their end-of-life, and the cluster must be expanded to accommodate a growth in the user base.

If a mixed GPU configuration is unavoidable, consider the following information when planning and designing within a Citrix Virtual Apps and Desktops VDI environment:

• Mixed physical GPUs are not supported within a single node. A single compute node can only contain a single physical GPU type.
• Each NVIDIA GPU model has its own set of NVIDIA vGPU profiles that are unique to that card model.
• Each chosen vGPU profile needs an associated Citrix Virtual Apps and Desktops gold image. These gold images add an administrative overhead because they must be either maintained separately or copied from a single parent gold image and the vGPU configurations that are applied to each subsequent related vGPU-enabled gold image.
• Separate Citrix Machine Catalogs must be created and maintained for each related vGPU profile. However, these can be placed into the same delivery group.
• Citrix Virtual Apps and Desktops will intelligently pick the appropriate hosts to deploy the NVIDIA vGPU pool to the correlated NVIDIA graphics cards within a vSphere cluster.
• Redundancy and failover considerations when you are expanding an existing vSphere cluster with a new GPU type include:
  • Adding two or more new identically configured nodes enables maintenance with minimal downtime.
  • Expanding by a single node provides no redundancy for that vGPU type. If you are considering adding a single node, it will be directly correlated with a machine catalog.
• If four or more nodes are required, deploy them as a new cluster.

Consult your Dell Technologies account representatives to discuss a long-term hardware life cycle plan that gets the best value out of your investment and solution.

Dell Technologies VDI Solutions allow for flexibility in networking selections. We have performed VDI validations with the following hardware, although several other choices are available:

• Dell EMC PowerSwitch S5248F (25 GbE ToR switch)—The S5248F switch provides optimum flexibility and cost- effectiveness for demanding compute and storage traffic environments. This ToR switch features 48 x 25 GbE SFP28 ports, 4 x 100 GbE QSFP28 ports, and 2 x 100 GbE QFSP28-DD ports. The S5248F-ON also supports ONIE for zero-touch installation of network operating systems.
• Dell EMC PowerSwitch S4048 (10 GbE ToR switch)—The S4048 switch optimizes your network for virtualization with a high-density, ultra-low-latency ToR switch that features 48 x 10 GbE SFP+ and 6 x 40 GbE ports (or 72 x 10 GbE ports in breakout mode), and up to 720 Gbps performance. The S4048-ON also supports Open Network Install Environment (ONIE) for zero-touch installation of alternate network operating systems.

For more information, see Dell EMC PowerSwitch S-Series 10GbE switches and Dell EMC PowerSwitch S-Series 25GbE switches.

VMware vSphere provides a powerful, flexible, and secure foundation for business agility that accelerates the digital transformation to cloud computing and promotes success in the digital economy.

vSphere provides the following benefits for VDI applications:

• Improved appliance management—The vCenter Server Appliance Management interface provides CPU and memory statistics, network and database statistics, disk space usage, and health data. These features reduce reliance on a command-line interface for simple monitoring and operational tasks.
• VMware vCenter Server native high availability—This solution for vCenter Server Appliance consists of active, passive, and witness nodes that are cloned from the existing vCenter Server instance. The vCenter HA cluster can be enabled, disabled, or destroyed at any time. Maintenance mode prevents planned maintenance from causing an unwanted failover. The vCenter Server database uses Native PostgreSQL synchronous replication, while key data outside the database uses a separate asynchronous file system replication.
• Backup and restore—Native backup and restore for the vCenter Server Appliance enables users to back up vCenter Server and Platform Services Controller appliances directly from the VAMI or API. The backup consists of a set of files that is streamed to a selected storage device using the SCP, HTTP(S), or FTP(S) protocols. This backup fully supports VCSA instances with both embedded and external Platform Services Controller instances.
• VMware vSphere HA support for NVIDIA vGPU-configured VMs—vSphere HA protects VMs with the NVIDIA vGPU shared pass-through device. In the event of a failure, vSphere HA tries to restart the VMs on another host that has an identical NVIDIA vGPU profile. If no available healthy host meets this criterion, the VM fails to power on.
• VMware vSAN Enterprise Edition—This edition includes all-flash, space-efficiency features (deduplication, compression, and erasure coding), software-defined, data-at-rest encryption, and stretched clusters for cost-efficient performance and greater hardware choice.
• VMware Log Insight—This tool provides log management, actionable dashboards, and refined analytics, which enable deep operational visibility and faster troubleshooting.

The architecture that this guide describes is based on Citrix Virtual Apps and Desktops, which provides a complete end-to-end solution delivering Microsoft Windows virtual desktops to users on a wide variety of endpoint devices. Virtual desktops are dynamically assembled on demand, providing users with pristine, yet personalized, desktops each time they log in.

Citrix Virtual Apps and Desktops provides a complete virtual desktop delivery system by integrating several distributed components with advanced configuration tools that simplify the creation and real-time management of the VDI. The following figure shows the architecture:

The Citrix Virtual Apps and Desktops components include:

• Studio—Studio is the management console that enables you to configure and manage your deployment, eliminating the need for separate management consoles for managing delivery of applications and desktops. Studio provides various wizards to guide you through the process of setting up your environment, creating your workloads to host applications and desktops, and assigning applications and desktops to users.
• Delivery Controller (DC)—DC is installed on servers in the data center. It authenticates users, manages the assembly of users' virtual desktop environments, and brokers connections between users and their virtual desktops. DC also manages the state of desktops, starting and stopping them based on demand and administrative configuration.
• Database—At least one Microsoft SQL Server database is required for every virtual application or desktop Site to store configuration and session information. The DC must have a persistent connection to the database because it stores data that the Controller services collect and manage.
• Director—Director is a web-based tool that enables IT support teams to monitor an environment, troubleshoot issues before they become system-critical, and perform support tasks for users. You can also view and interact with a user's sessions using Microsoft Remote Assistance. Starting in version 7.12, Director includes detailed descriptions for connection and computer failures, one-month historical data (Enterprise edition), custom reporting, and notifications using SNMP traps.
• Citrix Workspace app—The Citrix Workspace app is installed on user devices, and provides users with quick, secure, self-service access to documents, applications, and desktops from any of the user's devices including smartphones, tablets, and PCs. The app provides on-demand access to Windows, web, and Software as a Service (SaaS) applications. For devices that cannot install the app software, the Citrix Workspace app for HTML5 provides connectivity through a HTML5-compatible web browser.
• StoreFront—StoreFront authenticates users to sites, hosting resources and manages stores of desktops and applications that users access. StoreFront version 3.8 (released with XenDesktop 7.12) and later includes the ability to create and use multiple IIS websites each having its own domain name.
• License Server—The Citrix License Server is an essential component of any Citrix-based solution. Every Citrix product environment must have at least one shared or dedicated license server. License servers are computers that are either partly or completely dedicated to storing and managing licenses. Citrix products request licenses from a license server when users try to connect.
• Machine Creation Services (MCS)—MCS is a collection of services that work together to create virtual servers and desktops on demand from a gold image, optimizing storage utilization, and providing a pristine virtual machine to users every time they log in. MCS is fully integrated and administered in Citrix Studio. The following figure shows the MCS architecture:

  

• Virtual Delivery Agent (VDA)—VDA is a transparent plug-in that is installed on every virtual desktop or application host (RDSH). It enables the direct connection between the virtual desktop and users' endpoint devices. Windows and Linux VDAs are available.

Users can use a variety of client components to access the virtual desktops. The following table lists the client components that Dell Technologies recommends: