Checkpoint Sbx 166lhge 5 Manual 959 Skyway Road Suite 300. San Carlos, CA 94070. MAP International Check Point Software Technologies Ltd. 5 Ha'Solelim Street Tel Aviv 67897, Israel MAP.
-->One of the great benefits to virtualization is the ability to easily save the state of a virtual machine. In Hyper-V this is done through the use of virtual machine checkpoints. You may want to create a virtual machine checkpoint before making software configuration changes, applying a software update, or installing new software. If a system change were to cause an issue, the virtual machine can be reverted to the state at which it was when then checkpoint was taken.
Windows 10 Hyper-V includes two types of checkpoints:
- Standard Checkpoints: takes a snapshot of the virtual machine and virtual machine memory state at the time the checkpoint is initiated. A snapshot is not a full backup and can cause data consistency issues with systems that replicate data between different nodes such as Active Directory. Hyper-V only offered standard checkpoints (formerly called snapshots) prior to Windows 10.
- Production Checkpoints: uses Volume Shadow Copy Service or File System Freeze on a Linux virtual machine to create a>
- To see a list of checkpoints for a virtual machine use the Get-VMCheckpoint command.
- To apply the checkpoint use the Restore-VMCheckpoint command.
- In Hyper-V Manager, select the virtual machine.
- Right-click the checkpoint, and then select Rename.
- Enter in the new name for the checkpoint. It must be less than 100 characters, and the field cannot be empty.
- Click ENTER when you are done.
- In Hyper-V Manager, select the virtual machine.
- In the Checkpoints section, right-click the checkpoint that you want to delete and click Delete. You can also delete a checkpoint and all subsequent checkpoints. To do so, right-click the earliest checkpoint that you want to delete, and then click Delete Checkpoint Subtree.
- You might be asked to verify that you want to delete the checkpoint. Confirm that it is the correct checkpoint, and then click Delete.
- In Hyper-V Manager, right-click the name of the virtual machine, and click Settings.
- In the Management section, select Checkpoints.
- To allow checkpoints to be taken off this virtual machine, make sure Enable Checkpoints is selected -- this is the default behavior.
To disable checkpoints, deselect the Enable Checkpoints check box. - Click Apply to apply your changes. If you are done, click OK to close the dialog box.
- In Hyper-V Manager, right-click the name of the virtual machine, and click Settings.
- In the Management section, select Checkpoints or Checkpoint File Location.
- In Checkpoint File Location, enter the path to the folder where you would like to store the files.
- Click Apply to apply your changes. If you are done, click OK to close the dialog box.
- Log into your virtual machine and create a text file on the desktop.
- Open the file with Notepad and enter the text ‘This is a Standard Checkpoint.’ Do not save the file or close Notepad.
- Change the checkpoint to standard -- instructions here.
- Create a new checkpoint.
- Close the text file if it is still open and delete it from the virtual machine's desktop.
- Open Hyper-V Manager, right click on the standard checkpoint, and select Apply.
- Select Apply on the Apply Checkpoint notification window.
- Log into the virtual machine and create a new text file. If you followed the previous exercise, you can use the existing text file.
- Enter ‘This is a Production Checkpoint.’ into the text file, save the file but do not close Notepad.
- Open Hyper-V Manager, right click on the virtual machine, and select Checkpoint.
- Click OK on the Production Checkpoint Created Window.
- Close the text file if it is still open and delete it from the virtual machine's desktop.
- Open Hyper-V Manager, right click on the production checkpoint, and select Apply.
- Select Apply on the Apply Checkpoint notification window.
- Start and log into the virtual machine.
- Take note that the text file has been restored. But unlike the standard checkpoint, Notepad is not open.
Renaming checkpoints
Many checkpoints are created at a specific point. Giving them an identifiable name makes it easier to remember details about the system state when the checkpoint was created.
By default, the name of a checkpoint is the name of the virtual machine combined with the date and time the checkpoint was taken. This is the standard format:
Names are limited to 100 characters, and the name cannot be blank.
Using Hyper-V Manager
Using PowerShell
Deleting checkpoints
Deleting checkpoints can help create space on your Hyper-V host.
Behind the scenes, checkpoints are stored as .avhdx files in the same location as the .vhdx files for the virtual machine. When you delete a checkpoint, Hyper-V merges the .avhdx and .vhdx files for you. Once completed, the checkpoint's .avhdx file will be deleted from the file system.
You should not delete the .avhdx files directly.
Using Hyper-V Manager
To cleanly delete a checkpoint:
Using PowerShell
Exporting checkpoints
Export bundles the checkpoint as a virtual machine so the checkpoint can be moved to a new location. Once imported, the checkpoint is restored as a virtual machine. Exported checkpoints can be used for backup.
Using PowerShell
Enable or disable checkpoints
Configure checkpoint location
If the virtual machine has no checkpoints, you can change where the checkpoint configuration and saved state files are stored.
The default location for storing checkpoint configuration files is:
%systemroot%ProgramDataMicrosoftWindowsHyper-VSnapshots
.Checkpoint demo
This exercise walks through creating and applying a standard checkpoint versus a production checkpoint. For this example, you will make a simple change to the virtual machine and observe the different behavior.
Standard checkpoint
Apply the Standard Checkpoint with Hyper-V Manager
Now that a checkpoint exists, make a modification to the virtual machine and then apply the checkpoint to revert the virtual machine back to the saved state.
Once the checkpoint has been applied, notice that not only is the text file present, but the system is in the exact state that it was when the checkpoint was created. In this case Notepad is open and the text file loaded.
Production checkpoint
Let’s now examine production checkpoints. This process is almost identical to working with a standard checkpoint, however will have slightly different results. Before beginning make sure you have a virtual machine and that you have changes the checkpoint type to Production checkpoints.
Modify the virtual machine and Create a Production Checkpoint
Apply the Production Checkpoint with Hyper-V Manager
Now that a checkpoint exists make a modification to the system and then apply the checkpoint to revert the virtual machine back to the saved state.
Once the production checkpoint has been applied, noticed that the virtual machine is in an off state.
Generates a manual checkpoint in the SQL Server database to which you are currently connected.
Note
For information about different types of database checkpoints and checkpoint operation in general, see Database Checkpoints (SQL Server).
Syntax
Arguments
checkpoint_duration
Specifies the requested amount of time, in seconds, for the manual checkpoint to complete. When checkpoint_duration is specified, the SQL Server Database Engine attempts to perform the checkpoint within the requested duration. The checkpoint_duration must be an expression of type int and must be greater than zero. When this parameter is omitted, the Database Engine adjusts the checkpoint duration to minimize the performance impact on database applications. checkpoint_duration is an advanced option.
Specifies the requested amount of time, in seconds, for the manual checkpoint to complete. When checkpoint_duration is specified, the SQL Server Database Engine attempts to perform the checkpoint within the requested duration. The checkpoint_duration must be an expression of type int and must be greater than zero. When this parameter is omitted, the Database Engine adjusts the checkpoint duration to minimize the performance impact on database applications. checkpoint_duration is an advanced option.
Factors Affecting the Duration of Checkpoint Operations
In general, the amount time required for a checkpoint operation increases with the number of dirty pages that the operation must write. By default, to minimize the performance impact on other applications, SQL Server adjusts the frequency of writes that a checkpoint operation performs. Decreasing the write frequency increases the time the checkpoint operation requires to complete. SQL Server uses this strategy for a manual checkpoint unless a checkpoint_duration value is specified in the CHECKPOINT command.
The performance impact of using checkpoint_duration depends on the number of dirty pages, the activity on the system, and the actual duration specified. For example, if the checkpoint would normally complete in 120 seconds, specifying a checkpoint_duration of 45 seconds causes SQL Server to devote more resources to the checkpoint than would be assigned by default. In contrast, specifying a checkpoint_duration of 180 seconds would cause SQL Server to assign fewer resources than would be assigned by default. In general, a short checkpoint_duration will increase the resources devoted to the checkpoint, while a long checkpoint_duration will reduce the resources devoted to the checkpoint. SQL Server always completes a checkpoint if possible, and the CHECKPOINT statement returns immediately when a checkpoint completes. Therefore, in some cases, a checkpoint may complete sooner than the specified duration or may run longer than the specified duration.
Security
Permissions
CHECKPOINT permissions default to members of the sysadmin fixed server role and the db_owner and db_backupoperator fixed database roles, and are not transferable.
See Also
ALTER DATABASE (Transact-SQL)
Database Checkpoints (SQL Server)
Configure the recovery interval Server Configuration Option
SHUTDOWN (Transact-SQL)
Database Checkpoints (SQL Server)
Configure the recovery interval Server Configuration Option
SHUTDOWN (Transact-SQL)