Windows Backup and Snapshots

On Windows, most backup applications use Volume Snapshot Service (VSS) for the backup. Using VSS is required for backing up files in LDT GuardPoints. VSS service provides a consistent view of the data to backup and restore applications by taking a snapshot of the volume. Windows Backup uses the snapshot volume, while other applications can continue using the original volume for normal I/O operations. VSS snapshot volume uses a “Copy on write” mechanism to provide a consistent view of the data. Some of the high-level steps of the Windows backup process are:

1. Backup application takes a snapshot of the volume using the VSS service.

2. Backup application mounts this VSS volume to read the data to be backed up.

3. The CTE Agent uses the same policy as that of the original volume to protect these snapshots.

4. The CTE Agent applies the policy and rules to all the I/O requests coming from the backup and restore applications.