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For most VDI users, their virtual desktops are crucial to getting daily work done. As a result, VDI shops must ensure that their workers receive the applications they need. They also need to know that the VDI platform is delivering acceptable performance.
At its core, VDI is a way to deliver virtual resources, including desktops, applications and data to users. With VDI the desktops, applications and data run inside a VM in a data center, right beside the servers hosting them. VDI delivers the virtual desktops over a network to the device in front of the user. Organizations that adopt VDI often use it to deliver desktops to up to tens of thousands of users.
VDI monitoring products provide visibility into the state of the VDI deployment. Operations teams need these tools to resolve issues for individual users or groups of users such as those users in a remote office location. There are also requirements for capacity and configuration management for each part of the layers in a VDI platform.
Monitor the layers
VDI systems are made of many layers. All the layers must perform optimally for the user experience to be acceptable. This common eight-layer model addresses the major functional areas admins must monitor and manage. The eight layers are:
- The user's device. The device could be a zero client, thin client, desktop or laptop computer, or mobile device such as a tablet or smartphone. Users may have a variety of devices and some use multiple devices to access their desktops at different times. Different devices have VDI clients with different capabilities, such as different screen sizes or local device support.
- The user's local network. It might be an Asymmetric digital subscriber line, Fibre or Wi-Fi. It might be Wi-Fi in a hotel, coffee shop, library or office. For many VDI users, their local network is the wired network inside the company office where they work. For mobile users, it could be a mobile network, 4G, LTE or some combination of different networks over the course of a day.
- The connecting network. This is the network between the user's device and the data center. It may be the internet or the company WAN.
- Data center network. Admins have a lot of control here because it is the company firewall, routers and switches.
- VDI Gateway. Most VDI products have a gateway that allows secure access to a desktop VM from an untrusted network. Connections from the corporate network usually bypass this gateway because it is a trusted network.
- VDI broker. The broker is the center of the VDI product and determines which VM the user should access. The brokers also drive VM creation and destruction on the virtualization platform.
- Windows infrastructure. The options include Active Directory, file servers and database servers. This provides authentication and user specific configuration.
- Virtualization platform. This runs the desktop VMs using a hypervisor and some shared storage.
Many of the layers serve other purposes. Other applications share the network, both in the data center and in the user's device. Applications and other physical desktops also use the Active Directory and related Windows infrastructure.
A virtual desktop monitoring tool should be able to identify where in the layers problems reside as well as which components in each layer are functioning properly. Administrators need both a vertical view through the layers and a horizontal view across the layers.
The vertical view: User experience
The desktop VM's performance and the remote display protocol that streams the desktop's user interface to the user make up the user experience. Both aspects have multiple factors because there are many layers to each VDI deployment.
Most users cannot differentiate between a slow VM and a slow network that lead to poor remote display performance. Any VDI monitoring tool must be able to differentiate between the two because the resolution paths for these symptoms are completely separate. In a large VDI deployment, there will be big pools of resources, vSphere clusters, storage and networks.
One common mistake is to assume that because none of these large resource pools are stressed, that everything is functioning properly. Yet all of these large pools are made up of smaller units of resources, and smaller resource saturation can lead to a performance issue for a subset of users.
There are also many misconfigurations that can lead to poor desktop performance without any visibly constrained resources. One example of this is a Microsoft Distributed File System share with no root servers in the data center where admins deploy VDI desktops.
The horizontal view: Capacity management, compliance and security
Multiple users or their desktop VMs share many parts of a VDI deployment. Whether users share resources or not, admins must manage capacity and plan for load changes. The second aspect of desktop virtualization monitoring is to ensure that the shared infrastructure is healthy and has adequate resources. If the underlying infrastructure is saturated, then every VDI user will have a poor experience.
Managing the capacity for the desktops of hundreds, or thousands, of users is crucial. The common business expectation that monitoring desktops is unnecessary is a dangerous one. While one individual user's physical desktop has little effect on business, when the VDI infrastructure fails, every desktop fails which results in a significant company-wide problem.
Admins may choose VDI as the main desktop deployment method to accommodate a highly regulated or secured environment. The fact that all the desktops live within the data center gives them a great deal of control and allows them to implement much security oversight. The factors affecting this decision might be regulatory such as the Health Insurance Portability and Accountability Act and Sarbanes-Oxley Act. They may also deploy VDI to meet military classification and security requirements. These types of environments have very specific security and audit needs which may require features in a VDI monitoring tool rather than a general purpose security tool. Even in small corporate environments, desktop security is important in VDI because VDI desktops are inside the data center, one of the most trusted locations in the corporate network. Poorly secured VDI monitoring can be a significant information security liability.
VDI is complex and often critical to large businesses. VDI monitoring tools should allow operations teams to focus in on the experience of a single user, or groups of related users. Desktop virtualization monitoring tools should also provide visibility across the infrastructure layers to avoid problems that might affect large populations of users. The ultimate test of a VDI platform is whether it delivers the right applications and data to end users with a good experience. Effective VDI monitoring is about making sure users receive the best desktop experience both today and in the future.
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