Q: Any recommendations for hosting or streaming components such as .NET, Oracle Drivers, MQ drivers, teradata, DB2, etc ?   

A: Many core OS components will need to be installed as part of the base image. Things like anti-virus, drivers, .NET. 

Q: Is there a place to find this “Leverage Existing Infrastructure” slide or the info later on?

A: Yes. In the next few days there will be 3 articles released to the knowledgebase called: Simplifying Application Delivery to the Virtual desktop (Reference Architecture, Getting Started Guide and Implementation Guide).  The item you are interested in will be part of the Reference Architecture. 

Q: Can you elaborate on the nature of the Citrix Receiver? One of the main benefits to XenDesktop, supposedly, is that it’s clientless. It seems that the Citrix Receiver is a client…   

A: Nothing is clientless. Even a web browser is a client.  But in order to get to a virtual desktop, you will need a client application, the Citrix Receiver. Now the nice things about the Receiver is you aren’t forced to install 20 different clients. This one client will provide you with all the features needed to receiver your virtual desktop.

Q: Could we possibly see a demonstration of a virtual desktop session?   

A: You can take a look at the items on this page: http://www.citrix.com/English/ps2/products/demo.asp?contentid=163057#top

Q: If we pre-cache the app on the VDisk – aren’t we coupling the app with the vDisk. 

A: Not really. I consider installing an application to be coupling the app to the vDisk. Doing a pre-cache just optimizes the write cache so the app starts faster.  Remember, with streaming, the application is not installed and you only see the applications you have been granted.  Now if you have pre-cached an application and you now have an application update, do you update the pre-cache? Depends, of course.  If the update is major, meaning it changes many files, then I would update the pre-cache because these updates will cause the write-cache to expand. However, if the update is minor, meaning it only changes a few files, just update the application profile package and forgo the pre-cache updates. When the pre-cached application starts, the updates will be streamed down to the virtual desktop. This will increase the size of the write-cache, but because the updates are so small, the write cache growth will be small.

Q: Do you maintain a list of applications and how resource intensive they are?

A: There is a Citrix site called Citrix Ready (CitrixReady.com).  There are a fair amount of applications listed on that site. 

Q: For those of us who have not moved into the XenApp Realm yet and are trying to determine which product meet our needs, is there a better source of information, or a ‘buyers guide’ that helps us determine the correct path, XennApp, XenDesktop, etc?   

A: See if this document helps: http://www.citrix.com/%2Fsite%2Fresources%2Fdynamic%2Fsalesdocs%2FXenApp-XenDesktopTogether.pdf

Q: How many users can access a single vDisk from Provisioning Server with XenDesktop? An example…How many Provisioning and DDC servers will I need for 500 employees vs 1001+ Employees? 

A:   Take a look at this recently completed scalability document.  http://support.citrix.com/article/CTX119775

Q: If I still have to manage the client why would we want to create XenDesktop? I am not seeing the return based on the large infrastructure this will require to install.   

A: Excellent question.  There are many scenarios where it makes sense.  Below are a few, but there are many more. It all depends on your business and challenges experienced with the distributed computing model. # Forgo workstation upgrades but still utilize the latest Operating System and applications. Ever run Vista on an old workstation? You can now

  1. Use Desktop Appliances: They are slim devices that simply connect to a virtual desktop
  2. Remote users: Use your home computer without having to install apps or copy company data
  3. BYOC: Bring Your Own Computer allows you to use your own personal workstation while still having a secure and separate corporate computing environment.

Q: Since streaming is regarded as a primary delivery recommendation, how do you get the network team on board since they occasionally present resistance towards this distribution method 

A:   Yes, working with the network team is critical.  How much data do you think is transferred just to boot the OS?  Remember, we ONLY stream the parts needed. So even though Vista is gigs in size, we are only streaming about 180 MB of data.  XP is roughly 90MB. However, for enterprise deployments, you would want the physical design of the environment to have both ends of the stream to be in close/fast proximity.  The Provisioning Server should be located on the same high-speed network as the XenServers that will receive the stream for the virtual desktops.  This helps control where the network usage is going to occur. 

Q: You mentioned that if there are applications that need a lot of resources and they are installed on XenApp server they could hog the XenApp server.  Does XenApp have an HA (high availability) architecture that would allow distribution of the XenApp load dynamically to hot standby XenApp servers?   

A: XenApp does have a powerful load-balancing solution to distribute load based on any number of configurable parameters (CPU, memory, page swaps, user load, etc).  However, these algorithms only come into play during the start of a new session. Once your session is on a XenApp server, that session remains on the XenApp server until the session is closed.   So, you could wind up with a bunch of users on a XenApp server (which is good), until someone runs a resource intensive application that can potentially slow down the entire server because resources are shared. 

Q: You recommended Stream Applications for Base, Anomalous and Resource Intensive apps.  Stream from where, from XenApp? 

A: Yes, application streaming comes from XenApp.  The XenApp servers will manage application enumeration and launching. If you select a streamed application, you will obtain the stream from the Application Hub (like a file server) controlled by XenApp. 

Q: What is a hosted application?

A: A hosted application is one that executes remotely on XenApp.  All resources used are resources on the XenApp server.

Q: What happens when Provisioning Server goes down?  Are existing workstations cached and still working and only new stream requests are impacted?  Or are all workstations down? 

A: Because there is no local disk on the provisioned desktops, if Provisioning Server fails, the desktop pauses until the stream is reestablished.   This is why we recommend turning on the HA option for Provisioning Server.  This will help overcome this potential risk.

Q: When pre-caching the streamed apps, would you recommend storing those in the base OS vdisk or in a separate disk attached to the VMs?   

A: Pre-cache into the OS vDisk.

Q: When Streaming apps, will I run into problems when I have a suite of applications that make calls to each other. I.E. MS Office, Email and Document Management Systems?   

A: Not with XenApp 5 application streaming. In previous versions, applications could not talk to applications in different streams, but that challenge was overcome in XenApp 5.  So if you put Word, Excel and PowerPoint in separate application streams, they can still work together.

Q: Would this work for remote users, or is network connectivity required

A: Right now, you need a network connection.  But Citrix has announced Project Independence which provides a client-side hypervisor where we can think about doing offline virtual desktops. Take a look at the video: http://community.citrix.com/display/xd/independence

Q: What is the process for preparing an application for streaming?

A: You need to run through the installation of the application with the Streaming Profiler.  The profiler will take the installation and create an application package used for application streaming. Once the profile is created, you simply publish it like any other XenApp application.

Q: What is the typical time to first launch for a streamed application? 

A:  It depends on the application size and the network speed. When properly configured, the actual streaming of the application should be very fast, one or two seconds)

Q: What type of apps are not appropriate for this solution? 

A: There are still some issues with applications that install services on the system or install OS-level items (.Net, drivers, etc) .  Many of the other challenges have been overcome.

Q: Are streamed applications isolated to the extent that they are not aware of and cannot interact with another streamed application?  

A: Yes and no.  Yes in that what you say is correct. Streamed applications do not interact with other streamed applications. However, in XenApp 5 you can configure rules for the applications so they can talk to other streamed applications. It is a pretty cool feature that overcomes some major challenges with application streaming.

Daniel