Recently, I held Tech Talks for providing guidance to move a XenDesktop PoC to a production environment and you submitted many good questions, which is the reason why it required some time to provide you the answers. I covered most of these questions, however there were some that I needed to leave out because the question was not clear. Therefore, I would appreciate if you can re-submit these through the comments below so I can provide you the answer you are looking for.
Now, back to the questions and the answers to those.
Q: Are there any recommendations for using Anti-Virus (AV) software inside a golden image or the VMs? Is there any guidance for updates (both windows updates and AV updates)?
A: I would recommend to look at the XenDesktop Design Handbook, which provides information how to handle AV-related aspects in a VDI deployment. In addition, there is an Knowledge Center article “Provisioning Services Anti Virus Best Practices“.
Q: Can you provide links to resources on how to monitor and capture data related to IOPS during a PoC?
A: As a basic tool, Perfmon can be leveraged since it provides insights into what is happening from a desktop OS perspective. A number of its performance counters are useful for storage performance analysis: Physical Disk and Logical Disk counters, plus counters such as % DPC Time and Interrupts/sec from the Processor performance object. The following resources provide guidance for things to consider and watch for:
- Improper Storage Design for Virtual Desktops is a Killer
- VDI Resource Allocation
- Does Cache Trump IOPS
- I’m working when I’m Idle
Q: When will the Desktop Delivery Controller (DDC) and Provisioning Services support Windows Server 2008?
A: The Desktop Delivery Controller will be supported on Windows Server 2008 with the next release of XenDesktop. Provisioning Services is already supported in Windows Server 2008.
Q: What is “Idle Pool count setting”?
A: In XenDesktop, the Desktop Delivery Controller manages the number of virtual desktops that are idle based on the time of day. The idle settings enable administrators to control the number of virtual desktops that are started and ready for users to access at any given time. This ensures that a user “just” performs a logon to the virtual desktop providing fast access to the desktop itself instead of waiting for a virtual desktop to be booted.
Q: Are USB devices accessible on the virtual desktop, especially biometric scanners using IGEL Winestra 4210?
A: XenDesktop allows to map any USB device from the user’s endpoint device into the virtual desktop session if this feature is enabled. We have implementations with biometric scanners as well and I can only recommend to test your specific scanner type just to ensure functionality.
Q: When will XenDesktop 5 be released?
A: XenDesktop 5 is planned to be released by the end of this year.
Q: Why would you still use roaming profiles in a virtual desktop environment?
A: The user experience is a key aspect to ensure once moving into a VDI deployment, because the perception is with the introduction of new technologies that things will get better, meaning, you cannot sacrifice the user experience. This is even more important with users, who are driving the consumerization within an organization. Therefore, it is crucial to maintain the user preferences and settings within any environment. Considering the fact that a virtual desktop will be served from a shared, read-only vDisk and the Write Cache is deleted once the virtual desktop is rebooted, the entire user changes during runtime of this virtual desktops are lost and next time users accesses a desktop, they will need to start from the beginning. Would you like to reconfigure for example your Outlook signature, spell check etc. all over again every day? No, you want to just start and use the app as you left the day before. A roaming profile provides basic functionality to maintain these settings, however it is always recommended to optimize it for better performance, which includes folder redirection etc.
Q: Is a write cache applied only if a desktop is being streamed?
A: A write cache is applied as soon as one Provisioning Services vDisk is being shared by multiple VDI’s. The cache is the place where temporary writes occur since the vDisk itself is read-only.
Q: Are there any integration API’s to the PVS PXE services similar to Microsoft Automated Deployment Services (ADS)?
A: Provisioning Services provides several API’s that can be leveraged for integration purposes. These are:
Q: Can Provisioning Services HA be enabled for existing differential disks?
A: The built-in HA functionality can be used at any times for any disk type in Provisioning Services.
Q: Should only XenServer be used for PoCs or can I also use VMware ESX?
A: XenDesktop supports all three main hypervisors that includes besides XenServer also Microsoft Hyper-V and VMware ESX/vSphere.
Q: We have currently a VMware infrastructure – is it feasible to run a PoC in this environment or is a new environment required?
A: If you already have an existing VMware infrastructure and if this is going to be the platform for a possible production rollout, you can definitely leverage this environment. If this is a production environment, you should ensure that there is no conflict caused with the PoC environment, meaning from a networking perspective etc.
Q: Which hypervisor is recommended with XenDesktop considering performance aspects?
A: As stated before, XenDesktop supports all main three hypervisors. I recommend XenServer (Did you expect something else?) for several reasons: based on the fact that Citrix owns the code, we have much more options to tweak the maximum out of the hypervisor. Having said this, we already improved the scalability of XenServer in regards of XenDesktop and we will add even more. Some of these improvements are the following:
- Support for SR-IOV, which benefits Provisioning Services
- XenServer 5.6 FP1 will further improve XenDesktop VDI scalability and will introduce IntelliCache
Altogether this will enhance performance aspect of XenDesktop based VDI deployment.
Q: I am planning to implement virtual desktops with Thin Client in our college environment, especially for admin staff, who only use the office and the library. Will this work? Or could it be a problem?
A: You can use Thin Clients for many scenarios to lower the maintenance aspect of endpoint devices as well as limit the security risks for publicly exposed devices. The key question to answer here is if a Thin Client provides everything this user type needs. If this is the case, then there is no argument against it.
Q: How feasible is XenApp Desktop Virtualization to banking industry in developing countries?
A: A XenApp-based desktop virtualization, where a hosted-shared desktop is provided to users is a feasible solution. Looking at the vertical of the banking industry, there is a mix of solution based on how resources need to be provided to users – online apps, offline apps, or hosted-shared desktops. Considering a scenario, where endpoint device maintenance and security of these is a concern, Thin Clients receiving a hosted-shared desktop is a viable solution. From my own project experience in this specific sector, we did several large implementations covering all branches of a bank that are accessing resources in headquarter. However, providing a right answer is challenging without knowing the full background.
Q: What about the PoC Kit? Where does it fit in terms of the size of a PoC?
A: The PoC Kit has been designed and created for reducing the time of setup for a PoC. Therefore, some components have been merged into a single server such as the Desktop Delivery Controller hosting besides Web Interface also the License Server and Secure Gateway. However, the kit has no other limitations that would prohibit any scaling of it. Currently, the PoC Kit is going through an update cycle for the next release of XenDesktop and we will split up some roles from the Desktop Delivery Controller, which is probably more suitable for moving a PoC Kit type of implementation into production too.
Q: Does Citrix have a demo environment that can be leveraged by partners for customer demonstrations?
A: Yes, as partner you have the option to access the Virtual Computing Demo Center for a trial period. Please contact your account manager for further details.
If there should be any other question, please do not hesitate to post them here.
Senior Architect, Worldwide Technical Readiness
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