Application consistent snapshots

Cloud Snapshot Manager enables you to take application consistent snapshots by providing options to run Volume Shadow Copy Service (VSS) snapshots and custom scripts.

VSS snapshots can only be taken on Windows instances and is currently supported only on AWS and GCP cloud by Cloud Snapshot Manager. Custom scripts enabled snapshots are for Windows and Linux instances. In case of GCP, it supports custom scripts only for Linux VMs.

AWS: VSS snapshots can only be taken on Windows instances and is currently supported by CSM. Custom scripts enabled snapshots are supported for Windows and Linux.

Azure:

GCP:
  • Application Consistent Windows VSS snapshots are not supported. Windows Instance: VSS snapshots can be taken on Windows instances with image version v20160810 or later. The persistent disk must use an NTFS, exFAT, or ReFS file system.
  • Linux instances: Custom scripts enabled snapshots are supported. Deployment of the script is the manual process. Please see the Application consistent backup for GCP Linux VMs section.

Application consistent options are available in the Protection Plan page for scheduled snapshots and in the Resources page for 0n-demand snapshots. They are applicable only for VM resources.

For step-by-step instructions on how to create application consistent snapshots for each resource type (AWS, Azure and GCP), see the guide, Cloud Snapshot Manager Application Consistent Snapshots available on the Support site.

VSS snapshots

VSS is a Windows integrated service that enables consistent point-in-time backups of VSS-compatible applications. Cloud Snapshot Manager can successfully take VSS snapshots only if the Window instances are configured for VSS. This is currently applicable only for AWS VM resources.

If you select the VSS option for any non-VSS compatible VM, Cloud Snapshot Manager creates a crash consistent snapshot of volume. However, in such cases, the snapshot job status is only partially successful. In the snapshot detail section, you can view details that are related to whether the associated volume snapshot is VSS enabled or not.

Custom scripts enabled snapshots

There are instances where you would want to perform certain tasks before and after snapshot creation. For example, to pause read/write operations on the volumes before taking a snapshot and then resume the operations on the volumes after the snapshot is taken.

In Cloud Snapshot Manager, you can configure and run custom scripts (SSM documents for AWS) before and after snapshot creation. Cloud Snapshot Manager invokes these scripts during snapshot creation of VM resources. For information about monitoring the success or failure of the custom scripts, see Custom script execution status.

NOTE: Snapshots are created regardless of the script execution being successful or not. If there is any risk to the instance or application when a snapshot is created without the custom scripts having successfully completed, they should be run outside Cloud Snapshot Manager.

For successful creation of application consistent snapshots (VSS and custom scripts enabled), certain prerequisites have to be met in the cloud environment. For more information about the prerequisites, see Prerequisites for application consistency.