# Enabling GPU sharing on a Linux Amazon DCV Server
<a name="manage-gpu"></a>

With GPU sharing, you can share one or more physical GPUs between multiple Amazon DCV virtual sessions. For more information about sessions, see [Managing Amazon DCV sessions](managing-sessions.md). Using GPU sharing, you can use a single Amazon DCV server and host multiple virtual sessions that share the server's physical GPU resources. 

**Note**  
GPU sharing is only supported on Linux Amazon DCV servers.

**Prerequisites**

Before you begin, complete the following prerequisites:
+ Install the Amazon DCV server on a Linux server.
+ Install the Amazon DCV `dcv-gl` and `nice-Xdcv` packages on the server.
+ Ensure that the server has at least one supported NVIDIA GPU.
+ Install the NVIDIA GPU driver on the server. The official NVIDIA drivers are required. The open-source NVIDIA drivers aren't supported.
+ Ensure that the NVIDIA GPU driver supports hardware-accelerated OpenGL.
+ Install an X Server and configure the `Device` and `Screen` sections in the `xorg.conf` file.
**Note**  
You can use the `nvidia-xconfig` NVIDIA utility to automatically create an `xorg.conf` file and configure it for all the available NVIDIA GPUs.
+ Ensure that the X Server is running.
+ (Optional) Verify the Amazon DCV server configuration by running the `dcvgldiag` tool. For more information, see [Performing post-installation checks](setting-up-installing-linux-checks.md).

  You can also install the `nice-dcv-gltest` package and run the `dcvgltest` test application to check if the server is properly configured for GPU sharing.

To enable GPU sharing, you must specify the list of GPUs to be used by the virtual sessions. If you don't specify the GPUs, only the GPU used by the standard X Server, with the display name `:0.0`, is used.

Specify the GPUs in the `gl-displays` parameter in the `dcv.conf` file after you complete the prerequisites that are described earlier in this topic.

**To enable GPU sharing on a Linux Amazon DCV server**

1. Navigate to `/etc/dcv/` and open the `dcv.conf` file with your preferred text editor.

1. Add the `[display/linux]` section and the `gl-displays` parameter. Then, specify the available GPUs in the following format:

   ```
   [display/linux]
   gl-displays = [':xserver_port.screen_number_1',':xserver_port.screen_number_2', ...]
   ```

   Where *xserver\$1port* is the server and *screen\$1number* is the number that's associated with the screen related to the GPU. *screen\$1number* starts from `0`.

   The following example shows the `gl-displays` parameter for two GPUs running on the default X Server session:

   ```
   [display/linux]
   gl-displays = [':0.0',':0.1']
   ```

1. Save and close the file.

1. [Stop](manage-stop.md) and [restart](manage-start.md) the Amazon DCV server.