Citrix has been holding a series of webinars called the “VDI Expert Series”.

At the beginning of June we hosted a VDI Expert Series Webinar featuring two XenDesktop Customers: Todd Ericson of First Flight Financial Credit Union and Michael Love of Borland-Groover Clinic. You can view a recording of the webinar on-demand here. During the webinar we had many more questions than we could answer. Todd and Michael generously offered to answer as many of these questions as they could offline. Here are the results:

Questions & Answers:

Q: What kind of hardware are you running your XenDesktop VDI’s on and how many instances are you running on that hardware?

FFFCU: We are running Sunfire x2200’s (AMD) and Supermicro (Intel). All our machines are dual-socket and quad-core.

BGC: Our Hypervisors are utilizing dual quad core AMD CPUs with 64 GB of RAM; scalable to 128 GB of RAM. WE run 30-35 VMs per Hypervisor.

Q: Have you found thin clients a viable option for Desktop Steaming?

FFFCU: Yes, Thin Clients are viable for use as a streamed desktop.

Q: How many XP VMs are you running per host?

FFFCU: 25-50 Virtual Desktops per host

BGC: We have two XenServer pools. One pool hosts virtualized servers. The second pool hosts virtualized desktops only.

Q: Can XenApp streaming app support high resolution on VDI at (1900X1200)?

FFFCU: Yes, and it can do multiple monitors as well.

Citrix Note: Our HDX technologies continue to include many enhancements to ensure a high-definition user experience – screen resolutions and multiple monitor support are just some of the areas we continue to develop.

Q: Please talk about Storage optimization and how it optimizes the use of storage for individual desktops?

FFFCU: Provisioned Desktops only use one disk worth of space per type of image, no matter how many machines run from it.

Q: Do you allow your VM’s to run for the user continuously or force an idle timeout?

FFFCU: Both methods work. We do not use idle timers but we reboot all workstations at least once per week.

BGC: We force reboots of VMs on a weekly basis. This is to ensure users receive the most up-to-date image.

Q: Do you need separate desktop pools for images that differ only by RAM size?

FFFCU: Yes and no – Yes you need different provisioning pools but they can both use the same disk image.

Q: Do you shutdown VM’s when user logs off, and if so, how long does a connection request take if spinning up the VM. Also, do you use unique SID in AD for each VM?

FFFCU: The DDC handles all of the AD SID issues.

BGC: We do force shutdowns when a user logs off. Depending upon the idle pool count requirements another VM may spin up in its place. The idle pool count determines how many VMs you have waiting for a connection. If no idle VMs are available then the connection attempt will take substantially longer as the VM must boot up from a cold state (POST). VMs are created through Provisioning Server, which takes care of creating unique SIDs.

Q: Does any one have experience with the performance while running PACS in a medical environment?

BGC: Not yet, though we do run PACS software, which we’ll be utilizing shortly in XenDesktop.

Citrix Note: We have many customers running PACS on XenApp with excellent results and early POCs with XenDesktop have shown exemplary results for a variety of users across various networks.

Q: For credit unions using Symitar, hostnames of the PC’s dictate what resources should be available to that PC – how has Todd Erickson been able to cater to that for his credit union?

FFFCU: This is Symitar specific – VDI works as long as the hostnames stay the same.

Q: For Borland-Groover, if you don’t have Anti-Virus running on the virtual desktop how do you secure the gold image used to stream the virtual desktops?

BGC: We currently utilize AV on the virtual desktops. It has taken some tweaking as you don’t want the AV performing full system scans. Prior to deploying AV on the VMs we ran a scan of the gold image before deploying.

Q: How do you patch the “thick” dedicated VM? Do you leave them running all the time?

FFFCU: Thick VM’s are managed exactly like real PC’s. If you leave them on you can push updates to them, if you turn them off you probably want them to pull the updates in. Both methods work.

Q: How effective do the virtual desktops work across a WAN? Can you centralize the XenDesktop servers to central datacenters?

FFFCU: Virtual desktops work best when centralized. The bandwidth requirements are exactly the same as for XenApp (so 5-10 users per 128K of bandwidth, depends on many factors).

BGC: Extremely effective. We provide XenDesktop access to over a dozen remote locations from North to South Florida. Our entire XenDesktop infrastructure (Delivery Controllers, Provisioning Servers, XenServers) are housed in a central datacenter. This is the benefit of using Provisioning Server to stream to XenServer.

Citrix Note: Citrix HDX includes a broad set of technologies designed to enable a high-definition user experience for virtual desktops and applications. HDX Broadcast optimizes the reliability and performance of hosted virtual desktops and applications in a VDI environment over any network, enabling high definition user experience when accessed on the corporate network or from outside the corporate network for remote desktop access.

Q: I am a bit confused about the “Master Image” portion, as well as “streaming”. How does this take place so that machines have different names, making them recognizable by AD?

BGC: The master image is a single .vhd file stored on local or network storage. Provisioning Server is leveraged to create multiple AD accounts at a single time, each with unique names and SIDs. Provisioning Server is then able to stream each of those accounts to the hypervisor utilizing the master image.

Q: Mike, Can you comment on your experience with Dragon NaturallySpeaking in your XenDesktop environment?

BGC: Dragon works well for the most part. We’ve had one issue that we’re still working on. Dragon requires two methods of training: user audio and mic audio. The user audio files are unique to the user and can be stored in the user’s home drive, so the user only has to go through training once. The mic training, however, is unique to a combination of the microphone, user and computer. We are working through several possible solutions at the moment, including assigning particular VMs to physicians.

Q: To both, Are you running the AMD or the Intel processors, and for the Citrix group, what was the technical name or requirement for the processor to have?

FFFCU: We use both.

BGC: Our XenServers utilize AMD processors.

Q: What solutions do you have to use when you are managing remote users peripheral hardware and printers on customer’s site?

FFFCU: Citrix Profile manager works well, but there are many other solutions. Look for XenApp printing solutions and they will work with XenDesktop.

Q: Using this virtualization with laptops, how is the users experience when not connected to the network? Is the user able to maintain their desktop and re-sync when returned to the network?

FFFCU: There is no way currently to check out a desktop. I hear this is coming but we have not seen it or been able to test it.

BGC: You can stream an operating system from Provisioning Server to a client using PXE, though the client is not able to disconnect from the network while continuing to work.               

Citrix Note: With the release of Citrix XenClient, a Type 1 hypervisor, you will be able to allow users to roam offline and still retain their corporate -based desktop image. This will allow them to re-sync when re-connected to their network.

Q: What EMR software was Borland-Groover using and did you notice that there were any issues with the EMR software or with any others using XenApp or any other Citrix solution?

BGC: We are utilizing Nextgen for EMR and EPM. It has worked well under XenApp and XenDesktop. The only issue we’ve had is the result of using 32 bit hardware and operating system for XenApp.

Q: What extra administration tools are required to leverage VMware instead of XenServer for pushing out your images? We currently use VMware for imaging and will probably keep that environment moving forward.

FFFCU: No extra tools are needed. XenDesktop supports both platforms with no issue.

Q: What is bandwidth requirement for XenDesktop VDI solution to work on WAN?

FFFCU: My experience is 5-10 users per 128K of bandwidth – many factors can impact that number.

Q: What is the maximum resolution supported?

FFFCU: I am using 1680×1050 dual monitors with no issue.

Q: What pros does XenDesktop have over VMware View; both are very similar.

FFFCU: Supports physical machines as well as a bunch of other features.

Citrix Note: Citrix XenDesktop excels versus VMware View in key categories:

-         Best end user experience (over both WAN and LAN),

-         Offers a complete enterprise-class solution without 3rd party bolt-on requirements,

-         Field-proven single-image management,

-         An open architecture platform that doesn’t lock you into a single VM infrastructure.

 For more details, please visit -->this webpage.

Q: What type of WAN connections are in place? Is latency a problem?

FFFCU: Wan speeds of 256K – T1 speeds – We do bandwidth shape our sites to insure a good user end experience.

BGC: Our remote offices have MPLS links ranging from 3Mbps to 4.5Mbps. Latency is not an issue for us.

Q: What version of CSG and WI do they use?

FFFCU: We use CSG 2000 and WI 5.

Q: With the non-volatile images is it possible to not use Ant-Virus software?

FFFCU: Yes – and this is probably going to end up being best practice.

BGC: It is possible and we weren’t up until recently. We are currently testing Symantec Endpoint Protection concern being that it is still possible for a VM to become infected with malware, such as a self-propagating worm, that will remain resident until the user logs off.

Q: Is anybody running something like Cisco IP Communicator or softphone through their VDI or XenApp?

FFFCU: Yes – IP Communicator does work. Sometimes a bit tricky on the microphone

Q: How do you replicate images periodically to your DRP site? Any tool to automate this?

FFFCU: Depending on your back end storage solution, there are many options. There are also independent replication solutions that can be used. We do replicate all of the data offsite.

BGC: We aren’t yet doing this, though the images are flat .vhd files, so even a basic Robocopy task would work.

Q: What are the best practice guidelines for apps/users VDI is NOT adequate for, e.g. apps which require a lot of (RAM/CPU) resources?

FFFCU: We use XenApp for all high demand apps. I imagine that there is always the option to use a local desktop

BGC: You can scale VMs, so giving a particular desktop group more RAM over another is possible. If you want to shy away from VDI completely yet still offer remote access you can install the XenDesktop Agent directly on the user’s workstation.

Q: What version of Secure Gateway and Web Interface are you running with XenApp?

BGC: We are using Web Interface 5.1 with Citrix Access Gateways.

Q: How did you handle bloat in the user profiles?

FFFCU: Roaming profiles work OK and the new Citrix Profiles work well. Best thing you can do is redirect all of the main items to the users’ home share; this usually solves the profile issue.

BGC: We use a combination of profile redirection and Citrix’s Profile Manager. With profile redirection we can point Desktop items, Internet Favorites, My Documents and Application data to the user’s home drive. With Profile Manager we can better control what folders within a user’s profile are propagated to the network upon logoff.

Q: Are you using Provisioning Server and virtual disks?


BGC: We are using Provisioning Server to stream VMs from a single .vhd file.