VMware Desktop as a Service (DaaS) Overview

Short, animated video that outlines the benefits of VMware Horizon DaaS.



FREE eLearning: Horizon View V6 and Mirage V5: What’s New

The Horizon View V6 and Mirage V5: What’s New is a FREE 1-hour self-paced course which highlights the new features and enhancements in Horizon View V6 and VMware Mirage V5 product. Get to know the key features of Horizon 6 and walk through use cases for each of different product areas that make up this powerful end-user computing suite.

See the course details and get started today.

LSI Logic SAS vs VMware Paravirtual SCSI disk

Within virtual machines, there are different SCSI controllers available for writing the data to the actual disk. For the different operating systems, there are best practices which gives the best performance. Windows XP uses the BusLogic Parallel SCSI driver and the results are acceptable. With Windows 7 the commonly used controller is the LSI Logic SAS controller. Which is selected automatically when creating a virtual machine of this type.

Different vendors have different best practices, some of them advice to use the VMware Paravirtual SCSI controller. The VMware Paravirtual SCSI controller needs to be selected manually and needs some additional actions before it can be used. Creating a small additional disk with VMware Paravirtual SCSI controller connected will force the OS the use and installation of the correct driver. The additional drive can be removed after installation and the initial drive must be connected to the VMware Paravirtual SCSI controller.

The question is which of these controllers gives the highest performance. For that I have started some tests with IOmeter in a virtual Windows 7 machine. The first test was with the VMware Paravirtual SCSI controller and using an additional disk beside the system disk. The results of the test is show below:


The second test was performed with the LSI Logic SAS controller and was using the additional diks. This configuration could not give the same performance as the VMware Paravirtual SCSI controller, the results of this test are placed below


The other test we did was with the system disk instead of the additional disk. The same results are showed as the previous tests. The use of the VMware Paravirtual SCSI controller performs a little better then the LSI Logic SAS SCSI controller

The results of above are within the virtual machine, with Xangati i was able to measure from the outside. The following picture will show the light better performance of the VMware Paravirtual SCSI controller, where the first and last test includes the VMware Paravirtual SCSI driver:


For now, the conclusion can be drawn that the use of the VMware Paravirtual SCSI controller lead them a slight performance gain in these test.

Multiple Sessions in VMware Horizon View

When connecting to a floating pool using the View client, a user ended up receiving a new session despite having an existing session on another VM.

Analysis showed two desktop launch requests that came in from the same client connection in quick succession, spaced two seconds apart. Client log files imply the most likely scenario is that the user requested the desktop, immediately hit cancel on the wait dialog after the request was dispatched, and then launched it a second time. The View Connection Server correctly identified an existing disconnected session for the user while processing the first request at 13:18:57 for example, and provided the client with details to reconnect. The client dropped the Connection Server’s response and sent a second request at 13:18:59. This in turn was routed to the same VM, but the request was rejected as the first connection was still being set up by the View Agent. At this point the Connection Server then fell back to providing the user with a new session as the original was unavailable.


View 5.1.1 and onwards contains a hidden configuration option that will inform the Connection Server to not fall back and allocate a new session if it knows the user already has one, even if reconnecting to the session failed. In the specific case analyzed, if this was toggled the user would have received a connection error on the second launch request with the option to retry. Retrying a few seconds later would have succeeded.

VMware recommends that the option to disable the default fallback behaviour is enabled. Instructions for this are below:

  • Ensure connection servers are running 5.1.1 or later
  • Follow the steps to connect to the ADAM database at http://kb.vmware.com/kb/2012377
  • Navigate to the object CN=Common,OU=Global,OU=Properties,DC=vdi,DC=vmware,DC=int
  • In the Attribute Editor for the object, edit pae-NameValuePair attribute
  • Making sure not to adjust any other values, add a new string to the attribute with value “cs-allowfallbackfromexistingsession=0” (no quotes)
  • Click OK to close the editor dialog, your change is applied with no need to restart the servers
  • To reverse the change, edit the attribute again and remove the above line


To verify the fix has been applied, you may find the allowFallback value in a debug level line on any desktop launch. The line will have the following format:
<date-time> DEBUG <prefix> getSessionForApplication, userDn: <dn>, appMap: {<name>=<value>, […], allowFallback=false, […]}

Horizon View Client on Debian based Linux

Using the Horizon View Client on Debian (Ubuntu/Mint) based distributions gives some problems.  Basically, the solution is to use multi-arch and libssl0.9.8 from Ubuntu (i386). You will want the i386 packages even if you are using the amd64 build of Debian. Please note that if you have anything that relies on the Debian version of libssl0.9.8, installing the Ubuntu version of libssl0.9.8 as seen below will break those packages and apt will want to remove them! If you get an error in apt asking to remove a number of packages or needing to run apt-get install -f to fix broken dependencies, this is the case. Removing the Ubuntu version of libssl0.9.8 and reinstalling libssl0.9.8 from squeeze will resolve that.

The packages that we will be using from Ubuntu are from 12.04 which is based on Debian wheezy and is currently under long term support (LTS).

With that being said, here is how it works:

  1. (amd64 only) Enable multi-arch:
    dpkg --add-architecture i386
    apt-get update
  2. (Optional) Install GDebi Package Installer (gui package installer that handles dependency installation for you)
    apt-get install gdebi
  3. Download vmware-view-client_2.2.0-0ubuntu0.14.04_i386.deb
  4. Download libssl0.9.8_0.9.8o-7ubuntu3.1_i386.deb from here
  5. Install the Ubuntu 12.04 i386 version of libssl0.9.8. Just right click on the downloaded file and choose Open With GDebi Package Installer and click Install when it loads.
  6. Install the Ubuntu 14.04 i386 version of vmware-view-client Just right click on the downloaded file and choose Open With GDebi Package Installer and click Install when it loads.
  7. Now, vmware-view-client should be installed and available from Applications > Internet > VMware View Client.

This should work for both i386 and amd64, just make sure to follow the instructions above following your architecture’s instructions.