Application-Aware Writer

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. The Magnus Box Application-Aware Writer feature lets you 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 with Magnus Box. Some products that can be backed up this way are:

Oracle DB
MailStore Server
Microsoft Dynamics CRM
Microsoft SharePoint
Pervasive PSQL (Actian Zen)
Other products natively supported by Magnus Box, including Microsoft Exchange Server, Microsoft Hyper-V, and Microsoft SQL Server
Other products with their own VSS Writer

In early versions of Magnus Box, this 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 components

Click the Edit button (pencil icon) to browse the available VSS Writers installed on your device.

[SCREENSHOT: New Protected Item dialog set to Application-Aware Writer, showing the VSS Writer tree with selectable component checkboxes]

Select the top-most checkbox to include all components within the VSS Writer, or select individual components within the VSS Writer. For instance, the Microsoft SQL Server VSS Writer lets you select individual databases for backup. The VSS Writer itself may mark some components as non-selectable. These appear as a grey subcomponent with no checkbox.

VSS Mode

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

The actual behaviour of these modes is specific to each VSS Writer. The modes are a set of general-purpose options that each VSS Writer can implement in different ways. For more information, consult the documentation for your VSS Writer. In most cases, set it to the same mode you use for your regular backup job, usually either Full or Copy.

Backing up Oracle Database

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.

Use the Application-Aware Writer option and select the Oracle VSS Writer - ORCL component. Within 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 deduplicates them together and produces its own incremental backups.
If you take incremental backups at the VSS component, it may be slightly more space-efficient than the Magnus Box incremental system, because Oracle has a more specific understanding of the file formats. However, when restoring you must take care to restore the full backup and all incremental and log backups too, which adds complexity.

For more detail, consult Oracle's documentation for the Oracle VSS Writer.