The Windows agent supports full, differential, and transaction log backups for Microsoft SQL. Full and differential backups are performed using Volume Shadow Copy Service (VSS) snapshots. Transaction log backups are performed using the Virtual Device Interface (VDI).
Starting with Unitrends version 8.0, SQL differential backups use the VSS snapshots, as opposed to pre-8.0 versions which use VDI. With VSS snapshots, general performance is greatly enhanced, and features such as deduplication and replication are improved.
To implement the SQL differential performance enhancements, the following requirements must be met:
• Unitrends system must be running version 8.0 or higher.
• Windows agent on your SQL client must be version 8.0 or higher.
Note: After upgrading to version 8.0, the next differential is automatically promoted to a full backup. If your backup schedule only consists of full and transaction log backups, your schedule is not affected.
The following are considerations for upgrading SQL to Unitrends 8.0
• If agent push is used to update the agent, the next differential is automatically updated to a full with no additional action required.
• If you manually update the agent, you must re-save the client. Do this by going to Settings > Clients, Networking, and Notifications > Clients. Select the upgraded client and then Save. This forces the system to recognize the update to the client, and causes the next differential to be promoted to a full.