How do third-party SQL Server backup tools access database files for backup?

Question

I read about Red Gate SQL Backup, and I liked the concept of backing up a database that is compressed and writes a compressed backup to disk directly without an intermediate SQL Server backup.

And I wonder how this type of software backs up. Does it directly access database files? Is it using some kind of SQL Server or Windows API? Shadow copy of Windows?

Answer 1

SQL Server has an API for backup providers to connect items to the backup pipeline. See INFORMATION: SERIAL LIGHT on VSS and VDI backups in SQL Server or look at a Project with compressed SQL backup on sourceforge.

Additional Information:

• SQL Server Backup Application Provider Guide
• SQL Server 2005 Virtual Backup Interface (VDI) specification

Answer 2

It uses the "SQL Server " Virtual Device Interface (VDI) "according to the Datasheet .

Windows API SQL Server

CodeProject VDI wrapper,

Answer 3

SQL Server VDI - , . , T-SQL. , , .

, SQL Server .

By working this way, you can also use threads and concurrency to increase speed. Tools such as SQribe and Red-Gate Tools do this when performing circuit and data comparisons.