Friday, January 21, 2011

The Integration Services (Hyper-V Architecture part 3)

As I mentioned in my last post: When you install the IC, the VMs will be presented with some services:

·         Operating System Shutdown
·         Data Exchange
·         Heartbeat
·         Backup (Volume Snapshot)
·         Time Synchronization
·         Synthetic Devices (IDE, SCSI, Networking, mouse, video) (Not covered in this post)

As you can see, the IC provides more services than just the synthetic devices, and let`s take a closer look at each of the above.

·         Operating System Shutdown
With this enabled, the VM would be shut down from Hyper-V Manager when you select the ‘Shot down’ button. In other words, this would allow you to shut down the VM as you were logged into the console and issued the shutdown command. This is not the same as the ‘Turn off’ button in Hyper-V Manager. (In Norway, we actually call this the ‘Swedish button’..)

·         Data Exchange
This is the service that provides a way to exchange management data (FQDN, OsName, OsBuildNumber, OsMajorVersion, OsMinorVersion ++) between the Hyper-V host and the VM. The WMI can be called to use this information, and this one gives you the opportunity to use PowerShell to build management capabilities based on the obtainable result.

·         Heartbeat
This is the service that reports the state of health for the VM to the host. It is indicating if the VM is ‘alive’, and enables management agents to take actions based on the status of the VM.

·         Time Synchronization
This is the setting for the system clock. It keeps the VMs clock synchronized with the system clock of the Hyper-V host. You may find it useful to disable this service when the time (in a virtual environment) is different than the host time.  Also note that a physical machine has a battery-operated clock from which it gets its initial time when it is booted (unlike a virtual machine). So the VM would always get its initial time from the Hyper-V host regardless of the setting.  When the VM is up and running, and you are disabling this service, further synchronizations are disabled as well.

·         Backup (Volume Snapshot)
When you are using backup features that are dependent on Volume Shadow Copy Services (VSS), you need this one enabled. The result of unchecking this service would place the VM offline before a VSS backup is taken.

No comments: