Installing the QEMU Guest Agent for Application-Consistent Snapshots (Windows-based VMs)

Install the Quick EMUlator (QEMU) guest agent in your Windows-based guest operating system if you want to create application-consistent snapshots of your virtual machine (VM). For an overview of everRun snapshots, see Managing Snapshots.

Typically, while applications are running, they process transactions, open and write files, hold information in memory, and more. If you take a VM snapshot while your applications are still working, it is similar to restarting your system after a power outage. Although most modern file systems are designed to recover from this type of outage, it is possible that some data will be corrupted or lost in the process, especially while transaction-intensive applications are running. In this case, taking a snapshot without preparing your applications results in a crash-consistent snapshot, as if you took the snapshot after a crash or power outage.

Microsoft Windows provides the Volume Shadow Copy Service (VSS) that can inform the file system and your applications when they must temporarily quiesce or freeze their operations during a snapshot or backup. If your applications support VSS, the everRun software can signal your applications through the QEMU guest agent and VSS to quiesce during a user or Disaster Recovery (DR) snapshot on your everRun system, thus ensuring an application-consistent snapshot.

To install the QEMU guest agent

1. Log on to the everRun system with the everRun Availability Console.
2. Select a VM on the Virtual Machines page.
3. Click Console and log on to the Windows guest operating system.
4. To transfer the QEMU guest agent installer to your system, do one of the following:
   • Open a web browser and download the installer from the Drivers and Tools section of the Downloads page at http://www.stratus.com/go/support/everrun.
   • Mount a local network share that contains the installer and either copy it to your system or prepare to run it from the share.
5. Start the installer by double-clicking the icon. The QEMU Guest Agent Setup wizard is displayed.
6. Read the license information. If appropriate, click the check box next to I agree to the license terms and conditions.
7. Click Install to begin the software installation.
8. If Windows prompts that it cannot verify the publisher of the driver software, click Install to continue installing the software.

9. If prompted, click Restart to restart the guest operating system.

   When Windows restarts, you may see a message indicating that the driver software was installed.

10. If prompted, click Restart to restart the guest operating system again.

To verify that the QEMU guest agent is properly installed and running

Open Services. For example, click Start and Run, then type services.msc and click Run. Verify that the following services are present and running:

• QEMU Guest Agent (always runs)
• QEMU Guest Agent VSS Provider (may run only during quiesce)

Open Device Manager. For example, click Start, Control Panel, Hardware, and Device Manager. Verify that the following driver is installed and running:

• VirtIO Serial Driver (under System devices)

Related Topics

Configuring Windows-based Virtual Machines

Creating and Migrating Virtual Machines

Managing the Operation of a Virtual Machine