Archive for the ‘Citrix’ Category

CPU Masking for Citrix XenServer

January 21, 2011

I don’t usually blog much about Citrix just because I don’t spend much time with it.  This week I ran into a challenge that we occasionally used to run into in the past so I found myself having to do a little Citrix homework for a change.  The challenge is one of CPU differences between XenServer hosts.

Say you’ve got an established XenServer farm setup with 6 hosts that are all identical from a hardware perspective.  With this configuration you can take advantage of all the cool and time saving features that XenServer has to offer like XenMotion – the ability to hot migrate virutal machines between hosts.  But what happens after a year or two when you need to add additional servers to your farm but the servers and in particular the processors you have in the other 6 servers are no longer available?  I won’t go as far as to say “you’re screwed” but you would at least have to create a new farm with the new servers.  This is certainly not the end of the world but you are now managing two farms instead of one and have introduced more complexity to your environment.  All this due to the different feature sets of the different processors – which would proclude you from doing XenMotion across all of your hosts.

This was not only an issue for Citrix users but for VMware users as well.  VMware was a little quicker out of the gate to solve the issue by using CPU “Masking” which essentially dumbs down the newer processor to the same feature set as the oldest processor in the farm hence enabling the vMotion/XenMotion and other features.  There are obviously some restrictions to the types of processors that are compatible – you can’t make an AMD and Intel work together but like vendor processors within a generation or two of each other will usually be ok (check none the less).

So in doing my homework this week I was happy to discover that CPU Masking is now an available feature for XenServer.  This has been out for a few months now I just never looked into it until recently.  To take advantage of the feature you’ll need to upgrade to XenServer 5.6.  Once your there you should be good to go.  This will be very beneficial now that the newer servers are moving from 4-core to 6-core and 8-core architectures.  Using this feature you’ll be able to take advantage of the newer, faster procs and not have to rearchitect and migrate your existing farm around.  There is a pretty good article on the Citrix Community Blog with links to things like HCLs, test kits and other tools.  So check it out at the link below.




Remove the Client from Your Thin-Client (Sort of)

December 12, 2010

Virtual Desktop Infrastructure (VDI) is certainly nothing new but it is becoming more and more common in the market place.  There are very good solutions from all the major technology players like Microsoft, Citrix and VMware.  With VDI you are essentially moving your “desktop” to the datacenter and basically controlling your desktop as a remote session.  To do this you still need some sort of “client” to enable you to connect to that session.  There are lots of options out there but most have traditionally been small, dumb, “Thin Clients” with very little memory, no hard drive and keyboard, mouse and monitor connections.  There are other options like converting your desktop to a thin client or using something like an iPad but for the most part the dumb little thin client box is the most common.  The thin client has little or no moving parts and draws very little energy compared to a traditional desktop.  I would say they’re “cheap” but that could be argued either way with the falling costs of desktops and laptops.  Lets just say they are, for the most part, “more cost effective”.

Looking at the biggest players in the thin client market you’ll probably come up with Wyse and HP as the largest and then serveral other smaller companies like ChipPC, Pano Logic and several others.  One you probably wouldn’t think of is Samsung.  For awesome flat screen tv’s, absolutely, but thin clients?  Samsung came up with a very attactive option for thin computing – just a monitor.  I’d heard of these a few months back but really never had any first hand feed back on how well they worked until recently. The idea is simple, build the thin client right into the monitor itself.  Let’s face it the monitor is the one thing you just can’t get rid of no matter what your solution.  So I talked to one of our clients last week that recently implemented a few of these new thin client and they have been real happy with it.  It is a very clean solution.  No little boxes with cables coming out all over the place – just a monitor with a keyboard and mouse hooked up and one power cord.

The TC240 is a  24” LCD monitor with full feature thin-client.  It is capable of at least 1280 x 1024 resolution, have 256MB of RAM a 1Gb ethernet connection and a USB hub built in.  The thin client OS is Windows XPe to give you great flexibility and power.  You can find full specs for the TC240 here:

Looking for a PCoIP solution in a smaller monitor – they have that too.  Take a look at the 19” NC190 here:

I really like these Samsung monitor/thin clients as a VDI option just due to their pure simplicity.  Slap a monitor on the desk and hook it into your Citrix XenDesktop or VMware View environment and your good to go.  The only downside I have noted is there isn’t a model with built in wireless available.

XenServer and VMware vSphere – A Cost Comparison

July 24, 2009

I work for a reseller of both Citrix and VMware products.  In many client meetings we often debate over which virtualization platform a client should use for server virtualization and which one is “better”.  Now, if I were to ask all of our engineers (and I have) which hypervisor they would choose (XenServer or VMware) if all things were equal (price, performance, features….) they would almost unanimously say VMware vSphere/ESX.  As we know ALL things are seldom equal especially pricing and this is where the debate gets interesting.

 Usually the statement “XenServer is free which saves us lots of money.  Why should we look at VMware which is much more expensive?” comes into play at some point.  There is no question that this is a very valid point.  So let’s take a look at the two solutions and see where they net out.

First off, the blanket marketing statement “XenServer is free” is, in my opinion, not completely accurate.  If you are just looking for a base hypervisor that will let you consolidate servers, simplify management and perform some other basic feature then yes the “free” XenServer will work, so will ESXi or HyperV.  In fact, you won’t get much argument out of me that XenServer has the most rich feature set of all the free hypervisors.  That being said in most production environments there are going to be certain enterprise level features that you will want and in most cases need, like High Availability and the ability to “vMotion” or move vm’s live between hosts.

For me I see the minimum level of enterprise features being present in VMware vSphere Advanced and Citrix XenServer with Essentials for XenServer Enterprise.  Both of these solutions give you High Availability and vMotion and some other functionality.  So let’s take a look at what each one really costs.  I’ll use MSRP pricing and an environment consisting of 3 hosts.

VMware vSphere                                                                           

Advanced Acceleration Kit (3 servers)                                                                                                    $10,495

Platinum Support (24×7 unlimited)                                                                                                           $2,395

Total                                                                                                                                                                      $12,890


Citrix XenServer with Essentials Enterprise

Essentials for XenServer Enterprise ($2500 each)                                                                              $7500

24×7 Support (5 incidents max)                                                                                                                  $3000

Total                                                                                                                                                                      $10,500

 Difference                                                                                                                                                          $2390


Now, $2390 is still a decent chunk of money but all of a sudden the price gap between the two solutions is not nearly as drastic as $12,890 vs. FREE and this is a much more accurate comparison in my opinion.  Both products are very good and capable of running in a production environment and have similar core feature sets.  You should look at competing products before your spend your or your companies money but in my opinion and experience vSphere Advanced is well worth the extra $2390.  So test them both and you decide. 

So I guess the short answer to “Which one is better?” is the infamous IT answer “it depends”!

In my opinion some things to consider above and beyond price should include:

–          How proven is the solution in production environments?

–          How stable?

–          How easy is it to use and maintain?

–          How scalable?

–          How does it handle backups and DR?

–          General availability of third party products?

–          How well does it integrate with your storage?

Here are a few links to compare products:

VMware – vSphere – vSphere editions chart

Citrix – XenServer – XenServer Essentials

WYSE TCX Flash Redirection

June 26, 2009

When it comes to Thin Client computing there are several questions that typically come up.  The big one is usually “What about video performance?”.   Video performance was typically subpar or “choppy”, how choppy usually depending on what protocol (ICA or RDP) you were using.  WYSE responded with it TCX Multimedia Redirection software which significantly improved video performance by redirecting the processing associated with certain video files to the local client.

Now with the advent of more and more flash content in web pages and web apps, “What about flash video performance?” is becoming a much bigger concern.  Yet again WYSE is answering the call with its new TCX Flash Redirection software (still in BETA).  Whereas TCX Multimedia redirects video files to the local client, TCX Flash redirects flash video.  Now your end users can watch YouTube videos all day at work with minimal irritation and stop calling the help desk to complain.

Speaking of YouTube…..there is a good YouTube video demonstrating the flash video performance both with and without TCX enabled.  You can check it out here:

Here is a little technical documentation about the product as well:

TCX server components required for TCX Flash Redirection Tech Preview

–          Rich sound Server  ver.1.1.7

Supported Thin Clients:

–          V class and R class with XPe (WFR2 SP2 & WES) and

                                i) Rich sound Client ver. 1.1.7  (Only for Xpe Clients)

                                ii) MMR client ver.  (Only for Xpe Clients)             

–          V class Wyse Thin OS client (6.3.0_25)

Supported 32-bit operating system platforms:

–          XP Pro SP3

–          Vista (all flavors)

–          Windows 2003 Enterprise SP2

–          XenApp 4.5 & 5.0

Supported Protocols:

–          Microsoft RDP

–          Citrix ICA

–          Citrix PortICA

Supported Connection Brokers:

–          VMware View

–          Citrix XenDesktop

Supported Browsers:

–          Internet Explore Version 6

–          Internet Explore Version 7

Windows Server 2008 Terminal Server – Improved but No Replacement for XenApp

April 2, 2009

As a follow-up to my last post around the Windows 2003 TS / Citrix XenApp comparison I thought I’d create a high level summary of some of the changes made to Windows Server 2008 Terminal Server.  Most of this is summarized from a recent Citrix document that is very informative.  In general, most of the benefits listed in my previous post still apply to Windows 2008 and there is no question Citrix XenApp is still a much better solution for larger environments.  So let’s look as some of the improvements made to Windows Server 2008 from a Terminal Services standpoint over what is offered from Windows Server 2003 Terminal Services:

          Server Health Monitoring      

o   Ability to monitor and report on problems occurring in the environment. (XenApp adds automatic recovery options such as restarting the server)

          Printer Management Improvement: 

o   Ability to inherit existing printer settings of the local printer.

o   Ensures that local printers are isolated to that user specifically.

o   Client side printer can be restricted to only the default printer.

          Improved User Experience

o   Now capable of 32-bit color resolution.  (XenApp still limited to 24-bit)

o   More seamless application performance

o   Local audio playback now supported

o   Redirection of file types to the terminal server (client to server)

o   USB Printer and Storage support

          Performance Improvements

o   Session Sharing – increased application start time and reduces CPU and memory usage.

o   Display Data Prioritization – basically QoS for graphics apps.

          Application Compatibility

o   Basic SharePoint integration has been added.  (XenApp expands the capability)


o   SSL/TLS encryption now available

o   Policy-based control of client devices


o   Improved load-balancing

These are certainly good improvements over Windows Server 2003 but don’t even come close to the capabilities offered by the XenApp product.  Take a look at the complete 15 page document here to see the complete list of XenApp advantages.

Windows Terminal Server 2003 and Citrix XenApp: An Overview Comparison

March 22, 2009


In the last few weeks I’ve met with a couple different clients that use Windows Terminal Server to provide applications to their end users.  While their environments worked pretty well and were very cost effective, they still have some pretty common problems.  Performance was usually an issue depending on how many people were connected and what apps they were using.  Servers often had to be rebooted affecting all the users with connected sessions.  The conversation of whether to move to Citrix XenApp and why often comes up so I thought I’d put together a high level summary of some of the performance and end-user experience benefits of using Citrix over Terminal Server 2003.

First let’s start with Overall Performance.  Terminal Server is great for smaller environments and smaller numbers of users but if you have multiple servers that need to be clustered and support larger numbers of concurrent users XenApp wins hands down.  Here’s why:

          Virtual Memory Optimization:  XenApp performs DLL rebasing for application to reduce memory conflicts.  This improves your application performance and can enable a single server to support more concurrent users.

          Session Sharing:  Apps launched by a user automatically share the underlying terminal services session which gives you better server utilization.

          Universal Print Driver:  Reduces bandwidth and memory use and increases print times.  Advanced print options are also added.

          Session Bandwidth Tuning:  Enable the ability to fine tune a users experience.  This can be very effective when dealing with low-bandwidth challenges.

Application Response is the 2nd big advantage to using a XenApp solution.  Some of the advantages include:

          SpeedScreen:  Improves the performance of multi-media content and delivers synchronized audio and video to the client.  It also improves the web surfing experience with pages that contain Flash content.

          Session Reliability:  XenApp can keep sessions visible even when the network connection is lost.  This can be important especially if you’re using wireless for some of your endpoint devices.

          Smart-Card Support:  Auto-detect for apps that are smart-card enabled.

          Content Redirection:  Application can be automatically redirected to a local browser for better performance. 

          Native Multi-Monitor support

          Pass-thru authentication for Terminal Services sessions

Finally, Mobility is yet another advantage that XenApp has over standard Terminal Services.  These include:

          SmoothRoaming:  Allows users to move between different devices and maintain their sessions.  Support for SmartCards is also provided.

          Dynamic Display Reconfiguration:  XenApp automatically adjusts the session to the existing display which is usefully if users are moving between heterogeneous endpoint configurations.


These are just some of the advantages a Citrix XenApp environment can provide.  There are many more reasons to consider moving to a Citrix XenApp solution including advanced configuration options, compatibility, management, security and scalability.  So if you are currently using terminal services as a solution or considering it you should really look in to what Citrix has to offer and how it can provide an excellent ROI for your company.

WYSE Thin Clients in Your Environment

March 8, 2009

As VDI is used more and more across the enterprise, the use of thin clients becomes an obvious choice when it comes time to replace client hardware.  Some of the advantages to going the thin client route are:

          Cost – Thin clients are usually half the cost or less of a standard PC.  Prices can range from $200 to $500 generally.  Thin clients also need much less maintenance and support which is a huge cost for any company.

          Footprint – Thin clients take up a fraction of the physical footprint of a PC but more importantly they have a fraction of the carbon-footprint.  These devices usually draw around 10W of power compared to 80W+ of a PC.  If your company has hundreds or thousands of desktops this can mean significant savings on your power bill.

          Longer Refresh Cycles – because thin clients have no moving parts they don’t need to be replaced as often.  Where we see typical refresh cycles on desktops and laptops of 3 to 5 years, thin clients can go twice as long.  This also translated in to big savings for companies with a large desktop infrastructure.

There are many different manufactures for thin clients but perhaps the largest and most popular is WYSE.  WYSE makes a wide range of thin client devices from the most basic all the way up to a thin laptop client.  They also develop software specifically in this space such as their TCX Multimedia and multi-display capabilities. 

There are several “OS” choices to consider when you are looking in to thin clients for your environment.  You have 4 choices from WYSE:

          WYSE Thin OS – The simplest and lightest weight of the 4.  This is perfect for your most basic client needs.  It supports ICA and RDP protocols and is very inexpensive.  Examples:  S10, V10L

          Windows CE – The mid-range client OS which adds a local IE client and support USB CD-ROMs, ZIP drives and Smart Cards.

          Linux v6 – A full function scalable OS with a local copy of Firefox and Java.  It is fully customizable and supports all the functionality you would probably need.

          Windows XPe – The most robust of the 4.  Essentially a thinned down version of Windows XP.  Enables the ability to run local applications including video and Java.

I recently sat through a presentation from Citrix and WYSE demonstrating their latest and greatest and was very impressed.  If you are considering implementing a VDI solution for your business you should definitely check out their product line.  In most cases WYSE will give you free demo product to try-out for yourself.

XenServer Backups

March 1, 2009

We have seen Citrix XenServer becoming more and more popular as an enterprise level virtualization platform lately.  The question often comes up, “What is the recommended way to do backups of our XenServer environment?”   With virtualization platforms like VMware that have been around for several years now there are plenty of vendor based and 3rd party tools like VCB, Vizioncore vRanger Pro and Veeam to help you with backups.  XenServer and Hyper-V are relatively new to the game and don’t have as many options (yet).  After doing some research and talking with our Citrix resources I figured I’d put together some of the highlights of XenServer backups and a few links.

          Backup Agents:  Treat your VM’s like you would any physical server.  Install your backup agents such as Backup Exec, NetBackup or whatever it is you use and then backup normally.

          Storage Level Snapshots:  Leverage this technology whenever possible to provide point-in-time backups of your VM’s.

          3rd Party Vendors:  Check out 3rd party tools such as InMage DR-Scout to help re-evaluate your backup strategies.

For more technical/detailed instructions on backing up XenServer check out this great link from the site: