Citrix has just released a new version of the Citrix License Server VPX which are a self-contained Linux-based virtual appliance that allows you to easily deploy licensing in your Citrix environment. The requirement is only 256 mb which are sufficient for up to 500 Citrix servers and approximately 50.000 licenses. Currently the Citrix License Server VPX is only available for Citrix XenServer 5.6 Feature Pack 1 / Service Pack 2 or higher.

To get started download and import the Citrix License Server VPX Appliance via XenCenter and then configure hostname, dns suffix and ip address. If you’re testing this out I would recommend using the same name as your current Citrix License Server. This way you don’t need to return and reallocate all your licenses. Even though the hostname is the same it won’t register in DNS so you’re all safe.

Log on to your license server and import all your licenses and restart the appliance.

Most likely you’re using Citrix Policy to define your License server host name. Simply change this to the ip address of your new Citrix License Server VPX.

To be sure that everything is working properly you should stop your old Citrix Licensing Server Service. Then run the command : gpupdate /force and qfarm /load on one of your Citrix XenApp servers to verify that everything is okay.

If the Server Load is 20.000 there’s something wrong, most likely the hostname. Remember that this is case sensitive.

For those wanting to Return and then ReAllocate the licenses to a new host name please logon to your MyCitrix account.

So should you transfer all your licenses to this new Citrix License Server VPX appliance? That’s up to you, but since the current Windows version normally runs side by side with Remote Desktop Services Licensing it won’t make sense to me. On the other side this is a great way to setup a standby Citrix License Server for Disaster Recovery.

Resource :

• Citrix License Server VPX

Green IT was the hottest buzzword before Cloud entered the scene. For this reason there’s a lot of new servers configured by default by the manufacturer to provide the best balance between performance and power consumption. So what does this mean?

Well most of the HP servers delivered today are running with the CPU Core Speed 1,6 GHz instead of the intended 2,3 – 3,2 GHz. So to get the full power of your Citrix XenServer hardware you need to do some chiptuning in the BIOS. For HP servers you set HP Power Regulator to HP Static High Performance Mode (see main picture).

You can verify the before & after results by using the freeware CPU-Z to gather information about the CPU Core Speed.

Real world scenarios has showed that customers that has changed the BIOS setting to High Performance Mode has seen an increase in user density and much better application reponse times. This applies mostly to Citrix XenServer and XenApp / XenDesktop VM’s but also to servers running Low Latency Applications.

If you have a BIOS snapshot from other hardware vendors please send us an email so we can add it to this blog post to better help other people with similar problems.

Resources :

• Citrix XenServer – Optimise your servers for maximum performance
• CPU-Z

I’ve just recently moved to Brazil and for this reason I needed to build a new Citrix XenServer lab and restore all my Virtual Machines used in my xenapptraining.com course. Rebuilding the environment was not a option. So in this post I’ll describe my new hardware and how I managed to completely replicate the environment.

Citrix XenServer Hardware :

I purchased all the hardware in Norway except from the case that I bought here in Brazil. Be aware that I also bought an extra Intel network card as a backup in case I had problems with the network card on the motherboard. The issues with Realtek RTL8111/8186B is now solved with Citrix XenServer 5.6SP2 and 6.0.

So the total cost without case and network card turned out to be only $514,96. Pretty sweet for a 6 core – 16GB memory system. If you would like to boost the overall performance you could replace the SATA disk with a faster SSD disk. I prefer space before speed.

• ASUS M4A89GTD PRO/USB3, Socket-AM3
• AMD Phenom II X6 1055T
• Intel Pro/1000GT Desktop Adapter
• Corsair Dominator DHX DDR3 1333MHz 16GB
• Western Digital Caviar Green 1TB

Backup :

I’ve been running the awesome software PHD Virtual Backup for some time so I simply transferred the backup catalog to my laptop, packed my suitcase and went to Brazil.

Citrix XenServer Installation :

After I purchased the case in Brazil I needed to create a bootable USB stick to install Citrix XenServer. Back in the days we normally used Unetbootin for this, but this tool doesn’t work anymore with the latest releases of Citrix XenServer. This is how to create a bootable USB key with XenServer.

1. Format the USB key with Fat32
2. Download the latest copy of syslinux and extract it
3. Open a command prompt and change directory to your extracted syslinux\win32/64 folder
4. Run syslinux.exe X: – replacing “X” with the drive letter of your USB key
5. Extract the Citrix XenServer ISO. To mount it you can use Pismo File Mount
6. Copy the content of the extracted XenServer ISO folder to the root of the USB
7. On the USB drive, copy the content of the \boot\isolinux folder to the root of the USB
8. At the root of USB drive, rename the isolinux.cfg file to syslinux.cfg
9. At the root of USB drive, rename the isolinux.bin file to syslinux.bin

I started this project trying out the new Citrix XenServer 6.0 (How to install Citrix XenServer 6.0). There seems to be a bug with DYI hardware since the console on each VM was booting like slow motion, so I ended up installing XenServer 5.6 SP2.

Restore :

I imported and configured the PHD Virtual Backup for Citrix XenServer appliance and shared my backup folder from my local computer. In the beginning I had some problems getting access so I contacted support who quickly responded to my support ticket.

Turns out that you cannot have non-ASCII characters (ie. #,$,%….) in the password and PHD requires both Share and NTFS Full Control permissions. The restore is straight forward and only took a couple of hours.

Your System :

I would like YOU to share your home lab environment either it’s a DIY system or a HCL Citrix XenServer supported vendor in the comments below.

Here’s a new video showing you how to install Citrix XenServer 6 and enable IntelliCache in XenServer. IntelliCache is a technology that may reduce the requirements for central storage by as much as 90%. Be aware that this is a technology which is dedicated for XenDesktop using Machine Creation Services (MCS) only. Provisioning Server does not leverage IntelliCache technology today.

Select Enable thin provisioning (Optimized storage for XenDesktop) when installing XenServer. The installer will then create a Storage Repository which has thin provisioning enabled. You cannot enable thin provisioning after a non-thin provisioned Storage Repository has been created. This includes the case where you are upgrading from an older version of XenServer.

As a bonus we also show you how to import and configure the brand new XenServer Web Self Service appliance.

And here’s another great video : How To Configure Citrix Passtrough Authentication

People new to the virtualization space could get very frustrated when they find out that their Hypervisor of choice preforms much worse than a bare-metal installation. Haven’t the vendors and independent analysis like Project Virtual Reality Check stated that there is no longer any excuses for not running Citrix XenApp on a Hypervisor. The latest numbers shows that the performance are almost the same on XenServer, VMware and Hyper-V.

That being said, to get these high performances requires that you have done your homework and implemented all the Best Practices. Unfortunately there is way to many bugs out there and I’m not even going to start…but I have almost begged Citrix to pay more attention to their own Support Forum in this post.

In this post I’m going to share some important tunings related to poor network performance on Citrix XenServer 5.x family.

Disable Task Offload :

For Windows 2003 VM’s you will need to create a registry key to DisableTaskOffload – REG_DWORD = 1 under HKLMSYSTEMCurrentControlSetServicesTcpipParameter. The easiest way is to create a Group Policy to push this registry key.

Disable CheckSum Offload :

The second fix you should try if you still have poor network performance is to Disable Checksum on the XenServer interfaces, both the Virtual (VIF) and the Physical (PIF). Be aware that you don’t need to restart the XenServer or the VM’s. This script will do this automatically on all you network interfaces in your XenServer Pool.

echo Setting checksum off on VIFs
VIFLIST=`xe vif-list | grep "uuid ( RO) " | awk '{print $5}'`
for VIF in $VIFLIST
do
echo Setting ethtool-tx=off and ethtool-rx=off on $VIF
xe vif-param-set uuid=$VIF other-config:ethtool-tx="off"
xe vif-param-set uuid=$VIF other-config:ethtool-rx="off"
done
echo Setting checksum off on PIFs
PIFLIST=`xe pif-list | grep "uuid ( RO) " | awk '{print $5}'`
for PIF in $PIFLIST
do
echo Setting ethtool-tx=off and ethtool-rx=off on $PIF
xe pif-param-set uuid=$PIF other-config:ethtool-tx="off"
xe pif-param-set uuid=$PIF other-config:ethtool-rx="off"
done

Note :

Please note that this script is provided “as is” and that using this is at your own risk. Please feel free to leave comments below regarding bugs & suggested improvements in future releases.

5132 other Citrix Community members have already downloaded the eBook. It contains a lot of helpful information for both beginners and experts. Combined with the 7 day eCourse you will have a solid foundation to get certified as a Citrix Administrators. Check out some of these testimonials:

“I’ve used the the Hands On Guide for XenApp 5.0 extensively as a reference in my work. It’s been a great help to me”. John Martz – Illinois, USA

“Your guide was very helpful for me to get started with XenApp 5 and XenServer. I have deployed XenApp 5 using this on production environment and all looks good. Many thanks and keep up the good work!!!”. Manish N. Dwivedi – India

“Your web site has helped me greatly as I have now developed a test Citrix farm using your guide, this proved to be a great reference to follow when setting up a new 2008 environment with XenApp 5.0, not only does it cover installing XenApp but gives an insight into XenServer. Would highly recommend this web site and eBook to anyone from beginner to expert”. Nick Rimmer – Scotland

“I truly appreciate the work and the amount of time you spent in creating this amazing book. I found your book an excellent start to the world of Citrix XenApp. What I truly appreciate the most is the step by step instructions in about every little detail that goes with XenApp installation and settings. I wish I had your book a few years back when I first start learning about Citrix it would saved me a lot of hours and frustrations. Keep up the good work!”. Adam Tigris – Toronto

The Citrix XenServer 5.6 Beta is out and I would like to update one of my most popular blog posts. Here is instructions and also a YouTube video on how to install Citrix XenServer 5.6 to an external USB drive.

Mistyping is very common and I would recommend using the <TAB> key to auto fill. I have also included the DIR command so you will see the filename. This will make it easier when type pluss you will know how to do this for further releases.

1. Disconnect or disable all hard drives except the external USB drive
2. Download the Citrix XenServer 5.6 ISO
3. Boot and install XenServer 5.6 on your external USB drive, see installation video here
4. When the installation is finished, boot on the XenServer CD and press “F2″ when you see “Welcome to XenServer”

[youtube ahVDK1E0UxQ]

Command lines :

1. mkdir /tmp/sda
2. mount -t ext3 /dev/sda1 /tmp/sda
3. chmod -R 664 /sys/block
4. cp -R /sys/block/ /tmp/sda/sys/block/
5. chroot /tmp/sda
6. cd /boot
7. dir
8. mv initrd-2.6.27.42-0.1.1.xs5.5.901.760.1073xen.img initrd-2.6.27.42-0.1.1.xs5.5.901.760.1073xen.img.old
9. mkinitrd –with-usb initrd-2.6.27.42-0.1.1.xs5.5.901.760.1073xen.img 2.6.27.42-0.1.1.xs5.5.901.760.1073xen

ScreenShot of Commands :

The new CCEE and CCIA for Virtualization exams are starting to pop up. I have already signed up for the beta exam and I do have all the necessary hands-on experience on the different products. To learn the theoretical part I prepare by reading the Admin and Exam Preparation Guides.

I’ve been keeping an eye on www.citrixxperience.com and finally had time to review the 1Y0-A09 XenServer 5. The guide contains 202 well written questions which prepares you on the theoretical part. Highly recommended. Also check out the blog post “Preparing for a Citrix Exam – Tips from the Insider” by Kpayah Tamba – Exam Developer at Citrix.

The new version of Citrix Merchandising Server 1.2 (CMS) was released last week and the most important feature is Receiver for Macintosh, Download All feature, Receiver News and Receiver Forum links, Task-based video instruction, Enhanced browser support, Active Directory Server Backup and Receiver for Windows support for new languages. The Product Manager has told me that the Virtual Appliance for VMware will be available at 31th of March. Reading the eDocs today there is already a section called “Importing the Virtual Appliance into ESX“.

Upgrade Procedure :

To upgrade your CMS 1.1 logon to https://server/appliance – Configuration  - Upgrade Server and browse to the upgrade file that you have downloaded from myCitrix. See main picture.

After the CMS is upgraded and rebooted log on and select SSL Certificate Management – Export certificate signing request. Configure with your information.

Select Export and save the file. Open the cert file with WordPad and copy the content. Navigate to your certificate server or provider and paste the info.

Import the certificate back onto the CMS. The complete procedure can be found here or select “Click for example video” which is one of the new features taking you directly to Citrix TV.

Check your CMS configuration on the console to verify that you are using hostname instead of ip address and that you have added the hostname to your DNS server. Do a nslookup to test this under the Diagnostics menu.

Remember to download all the new plug-ins by selecting Plug-Ins – Get New – Download all.

After the upgrade was finished my lab Windows 7 client received this error message : ”There is an issue with the security certificate on the Citrix Receiver Merchandising Server at 10.0.10.6”.

I resolved this issue by opening https://cms.ctxlab.local and reinstalling the Citrix Receiver to get the proper certificate.

Most customers have delayed the upgrade to Internet Explorer 7 or 8 as long as possible. The reason is memory / CPU usage especially on Terminal Servers, but this applies to personal computers and VDI as well. Some of the biggest web pages in Norway have been promoting upgrades similar to YouTube and Twitter and now the Norwegian Center for Information Protection strongly recommend to upgrade. So Internet Explorer 6 is approaching its end of life and it’s time to move on.

A lot of projects these days are focusing on server consolidation leveraging virtualization to get more users on each hosts. Planning and Proof Of Concept is the essential to success. Don’t believe everything you hear about increasing user density / server by four times, avoiding purchase of additional hardware.

Okay, if you move your 3-5 year old Citrix environment to a hypervisor and stick to Citrix Presentation Server 4, Office 2000/2003 and Internet Explorer 6, maybe you will make it. What normally happens when you do projects like this, you upgrade to Citrix XenApp 5.0, Office 2007 SP2 and Internet Explorer 7 or 8 as well.

In this first post I will show you what happens with your memory usage when you upgrade Internet Explorer (IE). I have tested all the different versions of IE on 13 different web pages. The tests have been run on Windows 2003 SP2 and every IE version have been patched with the latest updates. IE have been open and closed after 1 minute and the memory usage have been recorded. The latest version of Adobe Flash / Shockwave and Sun Java have been installed with the Core Applications FrameWork.

Memory Usage :

Increase in Percentage :

Excel Spreadsheet :

From these numbers you can easily see that upgrading only Internet Explorer will have a huge impact on the maximum users per Terminal Server. In the next article in this blog series I will show you what you can do to reduce the memory usage with registry tuning and Citrix HDX Mediastream for Flash.

PS : Remember to Subscribe to RSS and connect to XenAppBlog on Facebook so you do not miss out on important news.

Many reports have showed that Citrix XenServer 5.5 scales better and optimizing for Citrix XenApp is done in a second. With VMware it has been, and still are more complex to tuning the guest OS. VMware claims 30% improved performance for Citrix XenApp hosted on vSphere 4. Feedback from customers and the new “Virtual Reality Check – VRC VSI and Clocks Reviewed 1.0.3” states the same.

Searching the web for Best Practices for Citrix XenApp hosted on VMware I discovered some resources I would like to share with you :