- 12.2.1. Creating a Multihead Group
- 12.2.2. Multihead Group Screen Indicator
- 12.2.3. Creating a Single Screen Across Several Monitors (Xinerama)
- 12.2.4. How to Create a New Multihead Group
- 12.2.5. How to Enable the Multihead Group Policy
- 12.2.6. How to Manually Set Multihead Group Screen Dimensions
- 12.2.7. How to Manually Set Multihead Group Geometry
- 12.2.8. How to Disable Multihead Group for a Session
- 12.2.9. How to Enable and Disable Xinerama
- 12.2.10. How to Disconnect a Secondary Client
A multihead group configuration enables you to merge and control multiple Sun Ray Clients, referred to in this context as heads, and their screens using a single keyboard and mouse attached to a primary client. The maximum number of clients that can be connected to a single Sun Ray session as a multihead group is 16, and a multihead group can be composed of virtually any mix of Sun Ray Clients. If you use clients that support up to two monitors, such as the Sun Ray 2FS Client or Sun Ray 3 Plus Client, then a multihead group can control as many as 32 monitors. Each Sun Ray Client presents an X screen of the multihead X display.
All peripherals are attached to the primary client. The remaining clients, called the secondary clients, provide the additional displays. If a secondary client tries to connect when the primary client is not available, a Waiting for Primary icon is displayed on the secondary client until the primary client is discovered.
Ordinarily, a multihead group session has a separate desktop toolbar and separate workspaces on each monitor. Windows cannot be moved from one monitor to another within the multihead group.
Xinerama, by contrast, enables all the monitors in a multihead group to be treated as a single screen. See Section 12.2.9, “How to Enable and Disable Xinerama” for more details.
If you hotdesk from a multihead group to a Sun Ray Client that is not part of a multihead group, you can still view all the screens created in the original multihead group on the single screen by panning to each screen in turn. This action is called screen flipping.
There are two main steps to create a multihead group:
Create the multihead group using the utmhconfig (GUI) or utmhadm command. The command must be run on the primary client. You can use a smart card to identify the terminals.
Enable the multihead policy using either the utpolicy command or the Admin GUI.
Note the following limitations:
The Sun Ray 2FS and Sun Ray 3 Plus Clients are designed to run a single display across two monitors without additional configuration, using a single frame buffer for two monitors, always treating them as a single, unified display surface to be controlled with a single mouse and keyboard and displayed to the X server as a single screen.
Video acceleration works only on the primary client. In a multihead group, the audio stream is directed only to the primary client, so audio/video synchronization is provided only on the primary client.
Regional hotdesking is not enabled for multihead groups.
When the multihead feature is used, a small window indicating the current session on each screen is displayed, with the current screen highlighted for easy identification. This window is automatically displayed for users during session creation. For example, Figure 12.2, “Multihead Group Screen Indicator” indicates that the user is on the second screen of a three-screen display.
The Xinerama extension to X11 creates a single large screen displayed across several monitors. With Xinerama, only one toolbar is displayed, and a window can be moved smoothly from one part of the screen to the next. When Xinerama is enabled, the RandR extension is automatically disabled.
For CDE desktop sessions, a single CDE toolbar and set of workspaces manages the configured monitors. A window including the CDE toolbar itself can span monitors, because the monitor displays are still within the same screen.
See Section 12.2.9, “How to Enable and Disable Xinerama” for more details.
Xinerama can also be used with the Windows connector uttsc command.
On the primary client, start the Multi-head Administration GUI.
# /opt/SUNWut/sbin/utmhconfig
On the initial screen, click Create New Group.
The Create New Multiheaded Group dialog box is displayed. The number of rows and the number of columns you provide are displayed as the group geometry when the group is created.
Follow the instructions in the wizard to complete the procedure.
The main step in the wizard is to select the clients within the multihead group and insert a smart card in each Sun Ray Client in turn to establish the order of the group.
Click the Finish button.
Exit the session or disconnect by removing your card.
Enable the Multihead policy.
See Section 12.2.5, “How to Enable the Multihead Group Policy” for more details.
Command-Line Steps
The following command enables the multihead group policy for the failover group and restarts the Sun Ray Software with the new policy on the local server without disrupting existing sessions.
# /opt/SUNWut/sbin/utpolicy -a -m -g your_policy_flags
# /opt/SUNWut/sbin/utstart
Issue the utstart command on every server in the failover group.
Admin GUI Steps
Click the Advanced tab.
Click the System Policy tab.
Select the Multihead Feature Enabled option.
Click Save.
If a system restart is needed, an advisory message will display.
Screen dimensions for the multihead group are automatically set, by default, to the largest dimension supported by the primary client.
To override the automatic sizing of screen dimensions, use the utxconfig -r command.
If explicit screen dimensions are chosen, or if the resolutions of the monitors differ, you may have problems with unwanted on-screen movement called panning, or large black bands around the visible screen area.
% utxconfig -rwidthxheight
For example:
% utxconfig -r 1280x1024
A multihead group can have its screens arranged in various configurations. For example, a user can arrange a multihead group of four screens as two rows of two screens (2x2) or as a single row of four screens (4x1). By default, when a user logs into a multihead group, the session uses the number of screens available. The layout or geometry of these displays is generated automatically.
When the mouse pointer is moved past the edge between two screens, it moves from one screen to the next. The geometry of the multihead group determines which screen is displayed at that moment.
You can use the utxconfig -R command to manipulate the automatic geometry.
Users can enable or disable Xinerama as part of their X preferences. The utxconfig command handles this setting on an individual token basis. The user must log off for the changes to take effect. When Xinerama is enabled, the RandR extension is automatically disabled.
Video acceleration is not available for Xinerama sessions. Video played without video acceleration can be dragged from one Sun Ray Client to another or can span multiple clients.
Xinerama tends to consume noticeable amounts of CPU, memory,
and network bandwidth. For optimal performance, set the
shmsys:shminfo_shmmax parameter in the
/etc/system file to at least
LARGEST_NUMBER_OF_HEADS *
width *
height * 4.
Log in to the Sun Ray session.
Enable Xinerama.
% utxconfig -x on
Log off the session and log back in for the changes to take effect.
Log in to the Sun Ray session.
Disable Xinerama.
% utxconfig -x off
Log off the session and log back in for the changes to take effect.
If you disconnect the secondary clients without deleting the multihead group to which they belong, the screens are not displayed on the single primary client. The primary client is still part of the multihead group, and the mouse cursor can appear to get lost when it goes to the disconnected secondary client.
To recover from this situation, you can do one of the following actions:
Reconnect the missing client.
Delete the multihead group using the utmhconfig or utmhadm command.
Replace the missing client.
Create a new multihead group that incorporates the replacement client.
