Personal vDisk – VM Test

The personal vDisk retains the single image management of pooled and streamed desktops while allowing people to install applications and change their desktop settings.

Unlike traditional Virtual Desktop Infrastructure (VDI) deployments involving pooled desktops, where users lose their customizations and personal applications when the administrator alters the base virtual machine (VM), deployments using personal vDisks retain those changes. This means administrators can easily and centrally manage their base VMs while providing users with a customized and personalized desktop experience.

Personal vDisks provide this separation by redirecting all changes made on the user's VM to a separate disk (the personal vDisk) attached to the user's VM. The content of the personal vDisk is blended at runtime with the content from the base VM to provide a unified experience. In this way, users can still access applications provisioned by their administrator in the base VM.

But, what happens if a personal vDisk runs out of space? Simple! Users will no longer be able to hold on to their customizations, allowing them access to only the base VM and the applications installed therein! This outcome beats the entire purpose of having personal vDisks! If this is to be avoided, then administrators should continuously monitor the usage of the personal vDisks, proactively detect a potential space crunch, determine what is causing the rapid erosion of space on the personal vDisk, and fix the root-cause, before desktop users complain. This is where the Personal vDisk – VM test helps.

For each Windows virtual desktop on the cloud, this test tracks the status and space usage of its personal vDisk and promptly reports errors / abnormal space usage. This way, administrators can accurately identify personal vDisks with very limited space, which virtual desktop such personal vDisks are associated with, and what is consuming too much disk space – user profiles? Or user applications?

This test is disabled by default. To enable the test, go to the ENABLE/DISABLE TESTS page using the menu sequence : Agents -> Tests -> Enable/Disable, pick Cloud Desktops as the desired Component type, set Performance as the Test type, choose the test from the DISABLED TESTS list, and click on the < button to move the test to the ENABLED TESTS list. Finally, click the Update button.

Target of the test : A Windows virtual desktop on the cloud

Agent deploying the test : A remote agent

Outputs of the test : One set of results for every user_on_poweredonvirtualdesktop

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The nick name of the Cloud Desktops component for which this test is to be configured.

Port

Refers to the port at which the specified host listens to. By default, this is NULL.

Inside View Using

To obtain the 'inside view' of performance of the cloud-hosted Windows desktops - i.e., to measure the internal performance of the Windows virtual desktops - this test uses a light-weight eG VM Agent software deployed on each of the desktops. Accordingly, this parameter is by default set to eG VM Agent (Windows).

Report Powered OS

This flag is relevant only for those tests that are mapped to the Inside View of Desktops layer. If this flag is set to Yes (which is the default setting), then the 'inside view' tests will report measures for even those Windows virtual desktops that do not have any users logged in currently. Such desktops will be identified by their name and not by the username_on_virtualdesktopname. On the other hand, if this flag is set to No, then this test will not report measures for those Windows virtual desktops to which no users are logged in currently.  

Is Cloud VMs

Since this test runs for a 'Cloud Desktops' component, this flag is set to Yes by default.

DD Frequency

Refers to the frequency with which detailed diagnosis measures are to be generated for this test. For instance, if you set to 1:1, it means that detailed measures will be generated every time this test runs, and also every time the test detects a problem.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG suite embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability
  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.

Measurements made by the test

Measurement Description Measurement Unit Interpretation

Personal vDisk service status

Indicates whether Citrix Personal vDisk service is running or not on this VM.

 

The values that this measure can report and their corresponding numeric values have been discussed in the table below:

Measure Value Numeric Value

Stopped

0

Running

1

Not installed

2

Note:

By default, this test reports the Measures Values listed in the table above to indicate the status of the Personal vDisk service. In the graph of this measure however, the same will be represented using the numeric equivalents.

Recompose status

Indicates the status of the initially provisioned disk or the updated image.

Number

Use the detailed diagnosis of this measure to know for which VM the initial personal vDisk provisioning or image update were unsuccessful and why. The VM can be in one of the following states:

  • OK – The initial provisioning or last image update was successful.
  • Disk Init – This is the first time that the personal vDisk has started or been resized. It is being initialized and partitioned by the service.
  • Disk Format – The personal vDisk is being formatted.
  • Updating – The initial provisioning or an image update is in progress.
  • Error (Disk Discovery) – An error state. An error occurred while discovering the personal vDisk.
  • Error (Disk Init) – An error state. An error occurred while partitioning or formatting the personal vDisk.
  • Error (Sys Init) – An error state. An error occurred while starting the Personal vDisk Service or configuring the personal vDisk.
  • Error (Update) – An error state. An error occurred during the initial provisioning or the last image update.
  • Unknown – An error state. An error occurred but the cause is unknown.

Space used by user applications

Indicates the amount of space used by applications installed on the personal vDisk attached to this VM.

MB

Personal vDisks have two parts, which use different drive letters and are by default equally sized.

One part comprises a Virtual Hard Disk file (a .vhd file). This contains items such as applications installed in C:\Program Files. By default, this part uses drive V: but is hidden from users.

These measures indicate how much space has been allocated to this .vhd file and how much of the allocated space has been utilized by user applications contained in this file.

A high value for the Space used by user applications and Space utilized by user applications measures is indicative of excessive space used by user applications. You can compare the value of these measures across VMs to know which user to which VM has utilized too much space reserved for user applications on the personal vDisk. If the value of the Space utilized by user applications measure grows close to 100% for any VM, it implies that potentially, the user to that VM will not be able to install any applications on the personal vDisk; nor access any applications.

Space allocated for user applications

Indicates the amount of space allocation for storing user applications on the personal vDisk attached to this VM.

MB

Space utilized by user applications

Indicates the percentage of allocated space used by applications installed on the personal vDisk attached to this VM.

Percent

Space used by user profiles

Indicates the amount of space used for storing user profiles on the personal vDisk attached to this VM.

MB

Personal vDisks have two parts, which use different drive letters and are by default equally sized. 

One part comprises C:\Users (in Windows 7) or C:\Documents and Settings (in Windows XP). This contains user data, documents, and the user profile. By default this uses drive P:.

These measures indicate how much space has been allocated to user profiles and how much of the allocated space has been utilized by user profiles.

A high value for the Space used by user profiles and Space utilized by user profiles measures is indicative of excessive space used by user profiles. You can compare the value of these measures across VMs to know which VM’s user profiles are consuming the maximum space on the personal vDisk. If the value of the Space utilized by user profiles measure grows close to 100% for any VM, it implies that potentially, the user to that VM will not be able to store/access any more documents or user data on the personal vDisk .

 

Space allocated for user profiles

Indicates the amount of space allocated for storing user profiles on the personal vDisk attached to this VM.

MB

Space utilized by user profiles

Indicates the percentage of allocated space that has been used up by user profiles on the personal vDisk attached to this VM.

Percent

Free space

Indicates the amount of unused space on the personal vDisk attached to this VM.

MB

Ideally, the value of this measure should be high. You can compare the value of this measure across VMs to know which VM’s personal vDisk has the least free space. You may then want to resize that personal vDisk to accommodate more data.

Total size

Indicates the total size of the personal vDisk attached to this VM.

MB

The minimum size of a Personal vDisk is 3 GB, however a size of 10 GB is recommended.

Space utilized

Indicates the percentage of space in the personal vDisk attached to this VM that is currently used.

Percent

A consistent increase in the value of this measure is a cause for concern, as it indicates a gradual erosion of free space in the personal vDisk of a VM.

By comparing the value of this measure across VMs, you can identify which VM’s personal vDisk is running out of space! Once the VM with the space-hungry vDisk is isolated, you may want to compare the value of the Space utilized by user applications and Space utilized by user profiles measures of that VM, to clearly understand what is occupying too much space in the personal vDisk – is it the user profiles? Or is it the user applications? Based on this inference, you can figure out which drive partition of the personal vDisk has limited free space, and can decide between freeing up space in that partition or allocating more space to the personal vDisk itself.