1. Launch the Citrix XenCenter client application on your Windows 10 machine. Ensure that any and all virtual machines running on XenServer have been shut down. This will eliminate any risk of destroying a virtual machine when allocating more memory to the Control Domain. After shutting down your virtual machines, click the Notifications button on the bottom of the left pane in the XenCenter application window.
2. Notice all of the Control Domain Memory Usage alerts in the pane on the right. An alert is sent every hour.
3. Return to the Infrastructure view by clicking the Infrastructure button in the pane on the left of the XenCenter application window.
4. To further ensure that no damage is inflicted on our virtual machines, we will place Citrix XenServer into Maintenance Mode. Ensure that XenServer is highlighted in the pane on the top left of the application window, then click the server tab on the ribbon at the top of the XenCenter application window. Select Enter Maintenance Mode from the dropdown that appears.
5. A pop up will appear and should be empty since our virtual machines have already been shut down. Click the Enter Maintenance Mode button at the bottom of the prompt to enter Maintenance Mode.
6. You can verify that Citrix XenServer is in Maintenance Mode by looking at the server properties in the General section in the pane on the right of the application window.
7. Now we can safely adjust the amount of memory allocated to the Control Domain. To begin the process, click the Server tab on the ribbon at the top of the application window and select Control Domain Memory… from the dropdown that appears.
8. A new pop up will appear where we can view the current amount of memory that is allocated to the Control Domain and adjust it as we see fit. Notice that there is currently only 0.8 GB of memory allocated. This is not sufficient.
9. Adjust the amount of memory according to your needs. Keep in mind that any memory allocated to the Control Domain will not be available to your virtual machines any longer. I am adjusting the memory on my XenServer’s Control Domain to 1.5 GB. Once the desired amount of memory has been entered, click the OK button at the bottom of the pop up window.
10. After the OK button is clicked, a confirmation pop up appears and informs us that a reboot is in order. We want to continue, so click the Yes button on the pop up.
11. Connection to XenServer will be lost while the machine reboots and applies the changes. XenCenter will attempt to reconnect to XenServer every 120 seconds until it successfully reconnects. Once reconnected, XenServer can be taken out of Maintenance Mode. Click on the Server tab on the ribbon at the top of the application window and select Exit Maintenance Mode from the dropdown that appears.
12. Finally, let’s clear all of those pesky alerts from our notifications view. Return to the Alerts view and click the Dismiss All button at the top of the pane on the right of the application window. Now our Alerts view is nice, clean, and empty.
That’s all there is to fixing the Domain Control Memory Usage alert in Citrix XenServer from XenCenter. Restart those virtual machines and enjoy your alert-free computing!