XenApp Components part 2

In the previous post I covered the basics of Citrix Licensing. In this post I will go over the different versions of XenApp.

There are three levels of XenApp

• Advanced Edition
  
• Enterprise Edition
• Platinum Edition

Here is table showing the difference in the three editions.

XenApp Components

This is the first of several posts detailing the different components of a XenApp (previously called Presentation Server) farm. I am going to make these short so that it is easy to read and remember.

Citrix Licensing Server

• FLEXLM licensing service that runs a Windows 2003 server with IIS installed. Same licensing service that VMware uses.
  
• Recommended that it is not on the XenApp server except for testing environments.
• License file model with files with .lic extensions.
• Administered from a web browser, a shortcut is placed off the Program, Citrix menu.
• The user that installed the service is the only user that can administer the licenses. Once logged into the management page additional users can be added.
• License files are tied to the hostname of the server and are generated/downloaded from mycitrix.com
• License files can be rehosted to a new hostname if you need to move it to a new server.
• If the license server is down the XenApp servers will function for 14 days without a connection to the license server. After that the servers will stop accepting connections.
• There is not a way to have more the one license server.

Link to Citrix support site on licensing server.
http://support.citrix.com/pages/licensing/

Hello Virtual World

Hello, this is my first blog post.

My name is Jeremy Waldrop, I am a Systems Engineer for Varrow. Varrow is an IT Consulting company focusing on virtualization and storage. I am focused on server virtualization from VMware and application virtualization from Citrix.

I have 10 years experience in IT and have worked for a consulting company for all 10. I have done everything from NT4 to Active Directory migration, Exchange migrations, Novell migration to Citrix WinFrame, MetaFrame, Presentation Servers and Cisco routing/switching.

This blog will be focused on virtualization, storage and DR.

XenServer Shortcoming

Here is another XenServer shortcoming when compared to VMware VI3.
http://www.theshonkproject.com/index.php?option=com_content&task=view&id=39&Itemid=1

VMware DRS Stars

I get this question a lot from clients "In VMware DRS what is a star? what percentage of CPU/memory equals a star?" I also have wonder what makes a star and how is a star calculated.

My usual response is that a star is calculated by some DRS algorithm and that there is no exact answer to what a star is. I have never really found anything that explains how starts are calculated. The closest thing I have found is in the VMware DRS white paper http://download3.vmware.com/vmworld/2006/mdc9694.pdf

• Level 1 – Apply only five-star recommendations. Includes recommendations that must be
followed to satisfy cluster constraints, such as affinity rules and host maintenance. This level
indicates a mandatory move, required to satisfy an affinity rule or evacuate a host that is
entering maintenance mode.

• Level 2 – Apply recommendations with four or more stars. Includes Level 1 plus
recommendations that promise a significant improvement in the cluster's load balance.

• Level 3 – Apply recommendations with three or more stars. Includes Level 1 and 2 plus
recommendations that promise a good improvement in the cluster's load balance.

• Level 4 – Apply recommendations with two or more stars. Includes Level 1-3 plus
recommendations that promise a moderate improvement in the cluster's load balance.

• Level 5 – Apply all recommendations. Includes Level 1-4 plus recommendations that
promise a slight improvement in the cluster's load balance.

If anyone out there has some more detailed information on how a start is calculated in DRS I would love to see it.