Bernard Baurin

An error occurred on an old Citrix infrastructure in production composed of servers PS 4.5 HRP 6 and of Secure Gateway 3.2 : at each launch of any application : a dialog box indicates a message like : “Cannot connect to the Citrix XenApp server. Protocol driver error”.

The article CTX106531 describes all the steps to follow for solving the problem : in my context, no solution was found. The tools used to analyse were the Windows Application log, the log error.log in the folder C:\Program Files\Citrix\XTE\logs. The only one error found was related to the ‘CGP downstream data’.

I have recreate the LCH with the well known following steps :

• stop the IMA service
• dsmaint recreatelhc
• restart the IMA service

And the problem was solved.

As you know, no tool or event ID is able to identify directly a corrupted cache. Maybe a good idea should be to plan the recreation of this cache, because I met this type of problem a time every year.

I have already worked with Citrix NetScaler 9.3 (NS) and never discovered this issue with NS 10 : with Windows 7 and IE 9, the management console is unusable, the menu having a dynamic behaviour and the content of the web windows remaining partial.

The only solution was to switch the compatibility mode from IE9 to IE8.

If you are using for instance the french version of AppCenter, you have probably encountered a little issue while assigning a load evaluator.

ISSUE

Suppose you want simply to use the built-in Load Evaluator ‘Advanced’. You agree its name is ‘Avancé’ and displayed as is in the AppCenter console :

When you create the new and assign the name of the Load Evaluator, if you write it with its name ‘Avancé’, instead of search it in the list ‘Calculateur de charge’, the affected servers will report a load index of 10,000 (full load), even if no users are using ressources on these XenApp servers.

EXPLANATION

A complete description is offered by Citrix on this issue : XenApp does not validate the load evaluator name when the policy is applied to user sessions. The cause here of our issue is that XenApp uses English names instead of french names displayed !

Citrix has provided a funny summary of tools used by the support team. If maybe some of theses tools are known, the global summary is interested for differents subjects such as XenDesktop, XenServer, XenApp and Netscaler.

Support Ninja Secrets

In a POC for testing business applications performance on a XenApp 6.5 farm, we encountered issues with the business applications during the scan requests : an error indicated the twain_32.dll could not be loaded.

At first, we believed that the applications were not compatible with RDS and we tried several known solutions as copy the dll in the ‘windows’ folder of the operating system, or in the ‘windows’ folder of the user’s profile used for the tests. The issue remained the same.

We have searched for the changes of configuration causing the issue : one the recommendations of the software editor was initially to uninstall the User Experience feature on the XenApp 6.5 / Windows 2008 R2 server.

After a new installation of the User Experience feature, the issue with the twain_32 dll disappeared.

Since 1995, I hold teaching certification MCT (Microsoft Certified Trainer), which allows me to provide training official Microsoft (during the famous OMC) in these approved centers.

This certification is renewed annually based on technical certifications and training carried out on the year just ended.

VMware offers to the technical architects a newest version of the document library, vCloud Architecturee Toolkit (vCat v2.0.1), very helpful to design and implement public, private or hybrid Clouds environments, including the technologies of vSphere 5 and vCloud Director 1.5. The library  provides guidelines detailed with use cases.

To read and study prior to initiating an architectural project !

Reminder : The ESXi hypervisor is the one component maintained in the new architecture.

VMware list the major steps to migrate VMware vSphere 4.x. to the 5.x version. The document VMware vSphere 5.0 Upgrade Best Practices describes all the combinations of cases for migration.

Major steps

Step 1 : Upgrade of the VMware vCenter server

Step 2 : Upgrade of the hosts to ESXi 5.0

Step 3 : Complete the upgrade of Virtual Machines

Step 4 : Upgrade the datastores to VMFS 5.

I was present at Citrix Synergy ™ in Barcelona, where Citrix announced the acquisition of App-DNA ™, a long-time partner. App-DNA is well known for its software suite AppTitude to facilitate the deployment of applications from Windows XP to Windows 7. It allows you to highlight the points of dependance to libraries, the security settings to review and the potential sticking points. It assesses the workload to produce according to the complexity of these different elements, which is particularly valuable when a planning has to be justified.

This acquisition follows major acquisitions made ​​in recent months, including:

• KAVIZA : in May 2011 for its VDI solution-in-a-Box destined for the SMB market;
• RingCube : in August 2011 for its desktop personalization solution in XenApp 6.5;
• ShareFile : in October 2011 for its solution of the storage and synchronization of documents on the Cloud.

This important technological evolution expresses the current mutation of Citrix’s office, now designed as flexible environment:

• any device : from the smartphone, the tablet to the laptop,
• anywhere : from the lan or a wan connection, in a online or offline context,
• any application : delivery of application on-demand,
• any data : with secure access to business data, from the availability on the Cloud, until the local storage on the endpoint device.

Citrix invites himself in the delicate phase of migrating applications that remains a difficult issue to be addressed in the projects of evolution of application services.

This POC was realized on a LAN configuration for all components, including the client devices.

NVIDIA MEMO

The graphic card NVIDIA Quadro FX 5800 installed in the HP blades, provides 240 CUDA parallel processing cores and therefore has the prerequisites for the GPU core codec.

PERFORMANCES

It is useful to consult the Citrix HDX 3D 1.0 Requirements Guide to understand the gains / performance limitations associated with the selected configuration of the POC.

A single monitor configuration was retained, the use of business application has been excellent. For a resolution of 2500 x 1660, the number of fps varied depending on the complexity of 3D operations requested, between 15 and 45 fps. The graphic computing capacity rose to the height requirements with a bandwidth of “only” 50 Mbps on the LAN.

ISSUES

Most of the time spent on the resolution was taken on the proper selection of the graphics driver version for configuring the HP / NVidia components.

CUSTOMER FEEDBACK

No break in use has been recorded by the client: for the choice of a resolution identical to the application running in a architecture no virtualized , the number of fps is so reduced by a factor of 10%, that is a very acceptable value.

The only brake on the spread of the Wan is the required bandwidth of 50 Mbps. The resolution being required, the decision was to limit the functional scope of the application for Wan connections, waiting to test the evolution of compression on the HDX versions later than 4.0.