You know that XenDesktop is the flagship product from Citrix and is one of the most completed VDI solution in the market, but is also quite difficult to implement in such a way to obtain the best user experience. Citrix has a lot of documentation on their website, but many people asked for a reference guide that could give useful hints to everyone is concerned with a VDI implementation.

The book Citrix XenDesktop 5.6 Cookbook, edited from Packt publishing and written by Gaspare Aristide Silvestri, an Italian It professional, is certainly a good refence manual for every IT professional who is working or is preparing a migration from a physichal to a virtual desktop environment. You can find also a review from this page of the Citrix blog.The author wrote this book using a step by step methodology, very useful to people approaching XenDesktop for the first time. Starting from some installation  hints on different hypervisor (XenServer, VMware, Hyper-V), the author explains how to configure all basic and advanced features and how to perform optimization activities to achieve the best environment for end users.
In every chapter, after a theorichal introduction (Getting ready section), there is a step by step guide (How to do it… section). Then there are a How it works and a There’s more sections with more detailed explanation and useful tips. At the end of each chapter there is also a lab section, to test the comprehension and to give the reader the possibility to create a full functioning environment.

I already know about XenDesktop product, but reading this book I have found many useful hints, for example all the optimization operations (registry key, etc) for the master image, from which all the other VDI are created. I found very useful also the chapter about XenDesktop Powershell modules, that give the possibility to made high-level configuration using command line.

I already read other Packt Publishing books about other Citrix products like XenServer and XenApp and this “Citrix XenDesktop 5.6 Cookbook” confirmed me that Packt is giving a great work about Citrix technical books and that their job could help all IT professional working with Citrix products.

I can say this book is an excellent starting point for learning about XenServer, whether you don’t know anything about virtualization, both for those are already familiar with other hypervisors, like VMware vSphere and Microsoft Hyper-V, and wants test / learn even XenServer.
As the author says in the preface of this manual, “The book starts by providing an overview of the XenServer platform and Resource Pool concepts. Next, it covers user authentication and storage repositories management. The book then dives deep into topics such as virtual machine creation and management, management of XenServer memory and networking, snapshots, and High Availability features and monitoring.”

According to me the strength of this book is without doubt the presence of numerous “practical examples covering typical tasks related to virtual infrastructure management.” Each of these tasks is then presented by the author (step by step) in two ways, using the GUI by XenCenter (the administrative console of XenServer) and are also listed the equivalent commands for those who want to use the xe cli, the hypervisor command line from Fort Lauderdale.

So I would recommend it to all those searching for a good guide to start using XenServer in their infrastructure, good job Daniele!

I was using a Windows Server 2003 virtual machine (x86) with SP2 and investigating this problem, the logs show that the error is due to an incomplete patching of the operating system. In fact, the setup invokes the sc.exe (Service Control Manager) command specifying the parameter sidtype, which is supported only from a specific patch, if none the installation hangs.

The solution is pretty trivial, proceeding with the installation of high priority patches, especially KB956572, which alone allows proper installation of the license server.
Obviously it is assumed that in a production environment critical patches are regularly passed, but it can happen that test or personal lab environments may include machines without some updates, in which case you can have these nasty surprises.
As you can see reading this article in the Citrix Forum this issue impacts versions of Windows Server 2003 both 32 and 64 bits.

So now Xendesktop 5.5 is out , including some new features from the recent acquisition (10th August) of Ringcube, and there is a new version of XenApp, which reaches the 6.5 release.
After some months of beta, the latest Citrix Receiver for Windows (3.0) and Mac (11.4) was also released and finally also Citrix XenClient reaches version 2.0.
So there are quite a bit of news to digest and studying, waiting for any others that are likely to be revealed to the public at Synergy EMEA the next October.
However, we will see what’s new in these new version in the next posts or you can read more in the previous links.
In response to this, today VMware has released version 5.0 of its vSphere hypervisor.

Here the images of 2010-2011 Gartner’s quadrants:

A couple of personal considerations: it is true that VMware remains the clear leader in the field of server virtualization,
as is also true that Citrix is ​​the undisputed leader in desktop virtualization, while Microsoft is still a step behind than these 2 competitors mentioned above. Another important thing in my opinion is that the XenServer platform has grown tremendously as a feature as well as adoption, given that more than 50% of XenDesktop deployments are using XenServer,not just because of costs, but based on performance and storage efficiencies.

Furthermore it is interesting to note that, after Gartner’s article, new versions of XenServer (6, now in beta) and vSphere 5, that should be released between the next month of August,have been announced. These new releases, along with several notable enhancements, are oriented to the cloud, a field where, as in the virtual desktop, Citrix is becoming the main antagonist of VMWare.
It’s important to note that, I’d like to talk in more detail in a later article, according to the news received so far about new vSphere licensing criteria, which provides a limitation on VRAM, it could result in many small businesses that use ESXi for free, migrate to different platforms, such as XenServer and Hyper-V, to keep their costs low.. I read many comments about this on the VMware Community (yes, I’m also a VCP…) and I’m waiting to have more precise information on the new licensing model, but it seems that with the free version of ESXi you will be entitled to use only 8 GB of vRAM! Nowadays this amount of RAM is used for some testing lab with the latest notebook…

In short, NFS is mentioned as a favorite mainly because it is simply to manage and inherently thin provisioned, and this is true with Creation Machine Service, while using the provisioning (PVS) things are a bit different …
I strongly recommend you read this article for further details of the case; furthermore just today (May 13th 2011) Citrix released the Service Pack 1 for XenDesktop 5, that exploits the caching mechanism (IntelliCache) provided the latest version of XenServer. This is a significant step forward in storage performance, since this technology allows you to greatly reduce the I/O on the storage, especially (but not only) during boot storm.

The rigorously pre-tested configurations enable customers to more easily leverage Citrix XenServer and IBM servers to automate datacenter management processes and increase efficiency of datacenter infrastructures.

This announcement expands the growing market momentum for XenServer in both cloud and enterprise datacenters. More than 50,000 enterprises worldwide now deploy XenServer for server virtualization, including 50 percent of the Fortune 500. XenServer also continues to gain share among cloud providers, building on the presence of the open source Xen hypervisor, the most widely deployed virtualization platform in the cloud. It is also the most widely used hypervisor for virtual desktops, hosting an estimated 2.5 million VDI-based desktops.

Considering that last week was also released the 4.1 version of Xen (upon which XenServer is based) and that some features of the actual version of XenServer have been specifically designed for use with the upcoming release of XenDesktop, expectations for the future of this hypervisor become very interesting.

Exactly, like the old days when the two companies were partners and fostered the integration of their solutions… As you know, although Citrix claims that XenApp running on XenServer will be able to have a density of users more of what you get with other hypervisors (there are reports from Tolly Group that provide the numerical values), there are a lot of realities in which the dear old Presentation Server is installed on the VMware platform.
So VMware made a guide that provides information about deploying Citrix XenApp in a virtualized environment powered by VMware vSphere. Key considerations are reviewed for architecture, performance, high availability, and design and sizing of virtualized workloads, many of which are based on current customer
deployments of XenApp application servers on VMware. This guide is intended to help IT Administrators and Architects successfully deliver virtualized applications using Citrix XenApp on VMware vSphere.
The following topics are covered in detail:

• VMware ESX host best practices for Citrix XenApp

• Virtual hardware, guest operating system, and XenApp best practices

• Monitoring performance

• vSphere enhancements for deployment and operations

Click here to download this best practice guide.

For the most part the product was rewritten.
Consider, for example, that the installation of the XD Controller is no longer supported on Windows Server 2003 (only Windows Server 2008 and 2008 R2) and it should not need more of Terminal Services and no longer use a IMA based architecture (in the previous version the DDC was based on legacy XenApp).
As we can read from this page of the corporate website here is what’s new in this release:

- Rapid virtual desktop management (management console)
The new Citrix Desktop Studio console lets IT administrators quickly build, test and update desktop images in one place, once, for everyone—just 10 minutes to install, 10 clicks to configure and 10 seconds to add new users.

- Efficient centralized support (console for helpdesk)
Citrix Desktop Director now gives helpdesk professionals a single desktop management console where they can monitor, troubleshoot and fix virtual desktops for 1,000 users as easily as for one.

- High scalability
The next-generation Citrix Delivery Controller can broker up to 15,000 virtual desktops from a single server.

- Integration with existing infrastructure
XenDesktop supports hypervisor technology and virtualization management from Citrix, Microsoft and VMware. A new comprehensive SDK lets you integrate and automate XenDesktop with your existing systems management infrastructure.

- Any endpoint device
XenDesktop enables more flexible virtual workstyles by letting users access their applications and data from any location through any device, including the latest iPhone, Android and Blackberry smartphones and the new generation of tablets.

- Anywhere, any user security with Citrix XenVault
Citrix XenVault secures corporate resources delivered to laptops owned by contractors or used by employeesunder a “bring-your-own-computer” program. Any data created by corporate applications is automatically encrypted and can be wiped clean centrally.

- High-definition video conferencing
HDX RealTime delivers high-definition webcam and video conferencing while consuming up to 80 percent lessbandwidth—enabling any user, anywhere to participate fully in real-time online communications and collaboration.

- High-performance peripherals
HDX Plug-n-Play now enables even faster printing from any location while using up to 90 percent less bandwidth. Simple, seamless use of USB devices, multiple monitors, MP3 players, scanners and digital cameras provides a rich and complete user experience.

- The most demanding applications
XenDesktop 5 refines the graphics experience with new enhancements that provide the highest quality while adapting to network conditions. New 32-bit color capabilities enables support for high-end graphics applications, while dynamic color compression adapts the color complexity based on network conditions.

- The right desktop for each worker profile
Flexible delivery options, including local VM, streamed VHD, personalized VDI and hosted shared desktops, enable you to meet the requirements of each user type in your organization—guest, remote, mobile, office and task workers—through a single desktop virtualization solution.

- Offline virtualization with XenClient
XenClient lets users work offline for greater flexibility and mobility while supporting VDI-like security and backup and recovery. A bare metal hypervisor lets centrally managed, encrypted virtual desktops run in a secure VM directly on the laptop.

- Authenticate once for any application
Users gain a single point of authentication to access all their applications—including Windows applications hosted on XenApp, Web applications and SaaS applications—through the Citrix Receiver interface, integrated with Citrix Cloud Bridge and Cloud Access technologies.

- On-demand Windows applications by Citrix XenApp
XenApp allows any Windows application to be hosted centrally and delivered for use while online, or streamed directly to the endpoint and run in an isolated environment for offline use.

- Self-service provisioning
Citrix Receiver acts as a storefront where IT can easily advertise available offline and online Windows and Web applications for easy download by users. Integration with Citrix Receiver enables fast, zero-touch install and configuration.

- Simplified, lower-cost application management
XenApp lets you eliminate system conflicts, reduce application regression testing and offload app workloads from physical or virtual desktops, greatly simplifying application management and operational costs.

You can also go here to view a video that provides everything you need to install and configure XenDesktop 5. There are just a few of the sections included in this tutorial: Installing the XD Controller and Virtual Desktop Agent Building and updating the Master Image using Machine Creation Service Evaluating HDX Technologies
Note: Although this video is titled “XD5 Express Edition” the exercises can be used with all editions of the product.

Certainly the new release made Citrix, once again, a step ahead in the VDI marketplace, with a great effort about scalabilty but also on making easier (if possible) the creation and management of a VDI environment. It’ true, fortunately for us who work in that field, that the optimization and tuning of these environments is and will remain subject to the chosen few IT professionals.

Wolf tested both XenDesktop 4.0 Service Pack 1 and VMware View 4.5, through a L2TP/IPsec VPN to connect from Europe to his facility in US. He connects to the XenDesktop and View environments one-at-a-time and perform a few basic tasks: opening a Word document and add a comment,then opening a browser-based Flash application (imaginationcubed), watch the sample drawing, and then use the app to write the word “hello.”
The verdict is clear: the two protocols are on par on LAN, while Citrix HDX performs better over WAN links with more than 200ms latency.

In fact Wolf Said “I found that as latency increased beyond 200 ms, ICA/HDX had a decided advantage over PCoIP. Text entry and menu response with ICA/HDX was still good enough to keep me productive, while the PCoIP response hampered productivity. When latency was relatively low (e.g., under 120 ms) both protocols performed well enough to meet my expectations. At several locations (i.e., Newark Airport, Munich, and Copenhagen) both protocols were able to deliver a good user experience.”

VMware has been very quick in addressing Wolf comments. The official reply was made by Scott Davis, CTO of the End User Computing business unit, who said: “…VMware View 4.5 with and PCoIP are configured out of the box to provide the richest LAN experience. There are several important parameters that can be adjusted to optimally tune the protocol for WAN conditions and specific usage scenarios. For WAN conditions it can be very helpful to adjust the display frame rate, image quality and min/max bandwidth settings. As an example, the default frame rate with PCoIP is 30. This can be safely cut down to 12 frames per second for WAN usage resulting in less bandwidth consumption and a better experience in many such circumstances…“
Davis doesn’t seem to disagree with Wolf about Citrix’s superior performance over 200ms latency links, but he certainly downplays the scenario: “Overall, this is a positive endorsement from a highly regarded unbiased analyst who validates a near equivalent user experience for PCoIP vs HDX for the majority of use cases. Customer scenarios range in bandwidth and latency, but conditions of latency above 200ms seem to represent a small minority…“

According to me this is the key-point: after that for many years the Citrix protocol was superior to any other, now PCoIp can offer a similar user experience, demonstrating that the gap between the two market leader VDI solution is reduced more and more and that VMware has done a good job in filling the delay that charges against his direct competitor from Fort Lauderdale.. Don’t forget that, also if some months later Citrix XenDesktop, also View 4.5 was defined from Gartner as an “enterprise ready” VDI solution.

If you want to read more you can follow these links from Alessandro Perilli website:
Citrix HDX better than VMWare PCoIP
VMWare answer to gartner