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  1. Home
  2. Veritas NetBackup™ Administrator's Guide, Volume I
  3. Section V. Configuring backups
  4. Creating backup policies
  5. Policy Attributes tab
  6. Use Accelerator (policy attribute)
  7. Accelerator and the Windows change journal
Veritas NetBackup™ Administrator's Guide, Volume I

Accelerator and the Windows change journal

For Windows NTFS and ReFS file systems, the Accelerator uses the Windows change journal to help identify the files that changed since the previous backup.

The extent to which the Windows change journal is used depends on the following:

  • Whether the Use Change Journal option has been enabled for the NetBackup client.

  • Whether the policy contains a schedule with the Accelerator forced rescan option enabled.

Note:

Regardless of the Use Change Journal setting or the Accelerator forced rescan setting, the Windows change journal always helps determine if a file has changed.

Table: How Accelerator uses the Windows change journal

NetBackup configuration

Accelerator use of change journal

The Use Change Journal option is not enabled

For full backups and incremental backups, NetBackup examines the metadata for every file to determine if the file has changed. Even without the Use Change Journal option, the Windows change journal helps determine if a file has changed.

The Use Change Journal option is enabled but the Accelerator forced rescan option is not enabled on any of the policy's schedules

The Windows change journal helps determine if a file has changed during both full backups and incremental backups.

  • During incremental backups, the Windows change journal is used exclusively to determine if a file has changed. NetBackup does not examine the file metadata.

  • During full backups, NetBackup examines the metadata for every file, to determine whether the file has changed. In addition, NetBackup uses the Windows change journal to help determine whether a file has changed.

The Use Change Journal option is enabled and the Accelerator forced rescan option is enabled on at least one of the policy's schedules

The Windows change journal helps determine if a file has changed during both full backups and incremental backups.

  • During incremental backups, the Windows change journal is used exclusively to determine if a file has changed. NetBackup does not examine the file metadata.

  • During full backups:

    • For a full backup schedule that does not enable the Accelerator forced rescan option:

      The Windows change journal is used exclusively to determine if a file has changed. NetBackup does not examine the file metadata.

    • For a full backup schedule that enables the Accelerator forced rescan option:

      NetBackup examines the metadata for every file, to determine whether the file has changed. In addition, NetBackup uses the Windows change journal to help determine whether a file has changed.

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