Full backup
After you configure your Azure SQL resources for backup, Druva performs a full backup of the databases on your server hosts based on the backup policy.
The Druva's Quantum Bridge executes a full scan of all the databases included in the backup. For FULL backups, the complete database is backed up everytime and then deduplication is applied. When the backup job is successful, Druva creates a recovery point in your storage.
Incremental backup (Change Data Capture-based)
When we take a FULL backup, the backed-up data might not be transactionally consistent. This means that if any transactions happen on the database during the backup, those changes will not get captured in the backup and we might lose out on that data.
To overcome this issue, our data protection solution utilizes Microsoft’s Change Data Capture (CDC) feature to track changes made to the database without modifying the original schema. CDC records changes made to the database such as inserts, updates, and deletes, and stores this information in special CDC tables, making it easily consumable for further use. You can use this information for taking incremental backups and syncing data across systems. Using CDC, you can have transactionally consistent copies of data for backup. For more information, see What is change data capture (CDC)?
Important:
Before taking CDC backups, configure the settings mentioned here. Failure to do so might result in the database being skipped from backups or failed backups.
CDC backup scenarios
This section describes different scenarios that might occur for CDC backups, the action Druva takes, and recommended actions required if any:
First backup scenarios
Scenario | Action taken | Recommended action |
CDC is disabled on the database. | Druva enables CDC on the database. For more information, see Backup Prerequisites. | Make sure you have the |
CDC is enabled on the database but there is a mismatch due to the following reasons:
| Druva skips that database from the backup and the backup completes with errors. | Configure the recommended settings for CDC backups and try again. For more information, see Backup Prerequisites. |
CDC is enabled manually | The database is considered for backup. However, Druva does not perform cleanup of CDC data post backup. | Cleanup the database by configuring recommended cleanup job settings. Set the retention parameter to minimum 1 day. For more information, see Backup Prerequisites. |
Subsequent backup scenarios
Scenario | Action taken |
CDC is disabled between backups. |
|
CDC is enabled on the database by Druva but does not match the required configuration. |
|
To enable CDC on database and tables, see Enable CDC on database and tables.