This article describes how to configure the Session Linger feature in XenApp.

Background

At times, users might close a published application unexpectedly. When they restart the same application, there might be a delay in the display of the application because the session creation and connection takes time. In such scenarios, the user can configure the Session Lingering feature to enhance performance.
Note: This feature is applicable for published applications. It does not work with published desktops.
Session lingering is not supported for iOS 

Instructions

Configuring the Session Lingering feature ensures that the user session is active on the XenApp server for a pre-defined duration. Therefore, when a user restarts a published application during that pre-defined duration, the user reconnects to the existing user session and accesses the application in a relatively faster time.

Create any one of the following policies using the Citrix Console to configure the Session Lingering feature:

• Linger Terminate Timer Interval - specifies the number of minutes a session remains active after the last application terminates. If a new application starts during this interval, the user session returns to the active monitoring state. If no application starts during this interval, the session ends.

  If this policy setting is not used, session linger is disabled.

• Linger Disconnect Timer Interval - specifies the number of minutes to wait after lingering begins before disconnecting the session. If a new application starts during this interval, the user session returns to the active monitoring state. It is possible that other factors may cause a session to be disconnected before the Linger Disconnect Timer Interval expires.

  If this policy setting is not used, a lingering session will not disconnect.

Apply the policy to the required user profiles or computers.

When a user to whose profile the preceding policy is applied to, terminates a published application, the Application State field is set to Lingering on the XenApp server, as shown in the following screenshot form XA 6.5.

Alternatively, the Application field is set to Lingering if a user terminates an application from a computer to which the policy is applied to.

When the user restarts the application within the specified time, the server detects that the session is still active for the user and connects the user to the same session.

Anonymous user sessions do not have a disconnected state; they are either active or terminated. Therefore, if the Linger Terminate Timer Interval and Linger Disconnect Timer Interval policy settings are used, the effective Linger Terminate Timer Interval setting is the same as the Linger Disconnect Timer Interval setting.

For a non-seamless named user session, the disconnected session remains in the disconnected state until the Linger Terminate Timer Interval expires.

7.X Environments:

For 7.X  environments, you can also configure Session Lingering Setting by Editing Delivery Group Properties as shows below:

• To enable session lingering follow the steps below:
  1. Open Citrix Studio
  2. In the left pane select Delivery Groups
  3. In the middle pane select the delivery group you want to modify
  4. In the right  pane  (Action pane) click Edit Delivery Group
  5. On the left side select Application Lingering and configure required settings.
  6. You can configure 2 behaviors:
     1. If lingering session will be created – by default lingering is disabled.
     2. How long lingering session remain active – there are two methods to specify how long an unused session remains active when the user does not start an application: a configured timeout and server load thresholds. You can configure all of them; the event that occurs first will cause the unused session to end.

Timeout – you can configure the time interval 1-99 days, 1-2376 hours, or 1-142,560 minutes.

Thresholds – you can configure two thresholds: the average load on all machines in the Delivery Group exceeds a specified percentage (1-99%) and the load on any machine in the Delivery Group exceeds a specified percentage (1-99%). When a threshold is exceeded, the sessions that have been in lingering state for the longest time are ended, sessions are ended one-by-one at minute intervals until the load falls below the threshold. (While the threshold is exceeded, no new lingering sessions are started.)

In order to verify if session lingering is configured you can do either:

• Select the delivery group in Citrix Studio. The result is shown in the Figure

• Run powershell cmdlet Get-BrokerSessionLinger. The result is shown in the Figure.

• Run powershell cmdlet Get-BrokerSession. The result is shown in the Figure

Citrix Documentation - Session Linger

CTX130793 - How to Configure Application Pre-Launch in XenApp 6.5