When beginning to think about desktop virtualization, you have two great options in either XenDesktop or VDI-in-a-Box, yet how do you choose?  Is it a matter of cost, environment size, features, and/or other factors?  Kumar Goswami, VP for our VDI-in-a-Box product, briefly talks about the topic in a blog post at /blogs/2011/12/01/citrix-vdi-in-a-box-v5-is-now-here-%E2%80%A6-give-it-a-go/.  He writes that “If you need simple VDI use ViaB.   Otherwise go with XD with its Flexcast offering.”  I think this is certainly a good summary and one of the main decision points.  Aside from choosing between a VDI-only offering and a Flexcast one, I’d like to discuss some other points here to compare and contrast the two products.  Hopefully the knowledge shared will help to sway folks in one direction or another based on their current situation.

Authentication – Both XenDesktop and VDI-in-a-Box support Active Directory as well as smart cards.  One key differentiator is that XenDesktop requires Active Directory and is not supported in a workgroup.  For smaller environments that use a workgroup with no central directory, VDI-in-a-Box may be the way to go since it also has the option of an internal user database.  On the flip side, when using Active Directory with VDI-in-a-Box, desktops need to be explicitly assigned to users or groups that directly contain users.  The use of nested groups and built-in Active Directory groups for desktop assignment would require XenDesktop. [UPDATE: As of VDI-in-a-Box 5.1, the use of nested groups and built-in Active Directory groups are both supported.]

Automation – XenDesktop provides an extensive PowerShell SDK interface that allows admins to automate tasks such as desktop creation, site configuration, and metrics collection.  VDI-in-a-Box is all about simplicity, wizards, and keeping the setup work and configuration options to a minimum.

Setup and Maintenance – As you might expect, VDI-in-a-Box setup and ongoing maintenance is significantly less involved than that of XenDesktop.  True, XenDesktop does feature the Quick Deploy option in which all components (license server, database, controller, consoles, etc.) are installed on the same system and a wizard walks you through the initial setup; however, this is only suitable for PoCs and smaller environments as there will be limited scalability and no redundancy.

High Availability – Both XenDesktop and VDI-in-a-Box provide high availability options at multiple levels.  Both support shared storage and redundancies in connecting to the environment.  XenDesktop has additional considerations for HA on the database; however, while VDI-in-a-Box uses local configuration files on each host as opposed to a central database.  VDI-in-a-Box also has the HA capabilities built-into the product with no additional requirements outside of adding two or more hosts to the grid.

Scalability – Initially you may think that XenDesktop is far and away more scalable than VDI-in-a-Box and that’s not exactly the case.  VDI-in-a-Box has been proven in customer environments serving up thousands of desktops across eight or more hypervisor hosts.  I would venture to say that this is sufficient for most businesses out there (keeping in mind that this is for a single deployment and multiple deployments can be created if needed to accommodate more users and/or different GEOs).  If you do require a single deployment serving up tens of thousands of desktops, XenDesktop might prove to be the better option.

Cost – I won’t go into the nitty gritty details here.  In short, if cost is a key factor for you VDI-in-a-Box is the way to go.  The required infrastructure, setup, and maintenance costs will be less than that of XenDesktop.

HDX 3D Pro – If you have specific needs to deliver high-end graphic accelerated desktops, you may want to consider the HDX 3D Pro feature available in XenDesktop Enterprise and Platinum editions.  Refer to http://support.citrix.com/proddocs/topic/xendesktop-als/hd-3d-about.html for additional details.

Policies – Both XenDesktop and VDI-in-a-Box utilize the same extensive HDX policy engine, although not all policies will apply to VDI-in-a-Box and VDI-in-a-Box requires the policies to be configured and stored in Active Directory.  XenDesktop allows the policies to also be configured and stored in the site database (for instances when you may not have control over AD) while VDI-in-a-Box allows you to configure on/off options for virtual channels within the product.

Well that’s about all I can think of for now.  Please let me know if I’ve missed any key topics here and what your thoughts are on the subject.  Until next time, stay virtualized… 🙂