VSS is a technology for taking a consistent point-in-time snapshot of a disk volume. A VSS Writer is an extra software plugin that detects when this action is taking place and ensures that application-specific files are in a safe state on disk. Magnus Box's "Application-Aware Writer" feature allows you to invoke a single VSS Writer, or a sub-component of a single VSS Writer, and back up only the files that it was protecting.

This is also an important third-party integration point for application vendors. If your third-party application includes a VSS Writer, you can use this Protected Item type to back it up using Magnus Box.

Some products that can be backed up with this Protected Item type are:

  • Oracle DB;
  • MailStore Server;
  • Microsoft Dynamics CRM;
  • Microsoft Sharepoint;
  • Pervasive PSQL;
  • other products natively supported by Magnus Box, including Microsoft Exchange Server, Microsoft Hyper-V, and Microsoft SQL Server;
  • and other products.

In versions of Magnus Box before 18.3.13, the Protected Item type was named "VSS-Aware Component".

NOTE: This Protected Item type is intended for integration with specific custom applications. If you want to back up normal files with a VSS snapshot, use the "Files and Folders" Protected Item type with the "take filesystem snapshot" option enabled.

Selecting componentsĀ 

In Magnus Box, click the Edit button (pencil icon) to browse the available VSS Writers installed on your device.

You can select the top-most checkbox to include all components within the VSS Writer, or you can select individual components within the VSS Writer. For instance, the Microsoft SQL Server VSS Writer allows you to select individual databases for backup.

The VSS Writer itself may mark some components as non-selectable. This is shown in Magnus Box as a grey subcomponent without a checkbox.

VSS ModeĀ 

You can perform the operation in "VSS Full", "VSS Copy", "VSS Incremental", or "VSS Differential" modes. If a specific VSS Writer does not support the selected backup mode, it will perform the backup in "Full" mode.

The actual behaviour of these modes is specific to each VSS Writer. For more information, consult the documentation for your VSS Writer.

Backing up Oracle DatabaseĀ 

Magnus Box can back up the contents of any installed VSS Writer using the "Application Aware Writer" option. Oracle Database officially supports backup via its installed VSS Writer.

You may need to install the Oracle VSS Writer separately. It is available with Oracle Database 11g and later (including 12c and 18c); newer versions of the Oracle VSS Writer can be installed separately to back up a 10g or 9i database.

You should use the "Application Aware Writer" option and select the Oracle VSS Writer - ORCL component. Inside this option, you can select individual tablespaces for backup, or select the entire component.

The Oracle VSS Writer reads the database with SYSDBA privileges.

The Oracle VSS Writer supports log, copy, full, differential, and incremental backups:

  • if you take "full" or "copy" backups at the VSS component, Magnus Box will deduplicate them together, producing its own incremental backups
  • if you take "incremental" backups at the VSS component, it may be slightly more space-efficient than Magnus Box's incremental system as Oracle has more specific understanding of the file formats. However, when restoring, you must take care to restore the full backup and all incremental/log backups too, that adds complexity.

More information about the Oracle VSS Writer is available in Oracle's documentation.

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