Azure SQL backup types, retention windows, and configurable limits vary by service tier and deployment option. Always verify exact limits for your tier in the official Azure docs: https://learn.microsoft.com/azure/azure-sql/database/automatic-backups-overview. The concepts here (full, differential, and transaction log backups; PITR; LTR; geo-restore) are broadly applicable.
| Backup type | Typical frequency | Purpose |
|---|---|---|
| Full backup | Weekly (typical) | Contains data files plus log records needed to make the backup consistent. |
| Differential backup | Every 12–24 hours | Captures page-level data changes since the last full backup (smaller and faster than full). |
| Transaction log backup | Every 5–10 minutes | Captures transaction log records to enable PITR within the configured retention window. |

- Full backup: the database data files plus the transactional log records required to make the backup consistent.
- Differential backup: only data page changes (delta) since the last full backup.
- Transaction log backup: transaction log records only; used to replay transactions and perform PITR within retention.
| Restore scenario | When to use it | Notes |
|---|---|---|
| Point-in-time restore (PITR) | Recover recent data or undo recent changes | Restores to any point within the configured PITR retention; creates a new database with a new name on the same server/instance. See: https://learn.microsoft.com/azure/azure-sql/database/point-in-time-restore |
| Restore deleted database | Recover a dropped database | You can restore to any point within retention, including the time of deletion. Must restore to the same server or managed instance. |
| Geo-restore | Primary region unavailable or disaster recovery | Uses geo-replicated backups to create a new database on any existing server/instance in another Azure region. See: https://learn.microsoft.com/azure/azure-sql/database/geo-restore-overview |
| Long-term retention (LTR) restore | Regulatory or archival requirements | Use LTR snapshots retained for weeks, months, or years (up to 10 years) to restore older snapshots beyond PITR limits. See: https://learn.microsoft.com/azure/azure-sql/database/long-term-retention-overview |

- Open the Azure portal and navigate to SQL databases.
- Select the database to inspect (for example, a migrated database).
- From the database page, click the server name to open the server overview.
- On the server overview, choose Backups.

- Point-in-time restore (PITR) retention — set how many days of PITR you require (max varies by service tier; many tiers allow up to 35 days).
- Differential backup frequency — tune differential backup frequency (for example, 24 hours) to balance recovery granularity and storage.
- Long-term retention (LTR) — configure weekly, monthly, and yearly LTR snapshots and their retention durations (LTR supports retention up to 10 years).

When restoring a deleted database, you must restore to the same server or managed instance from which it was deleted. For cross-region recovery when the primary region is inaccessible, use geo-restore instead (this creates a database on a different server/region using geo-replicated backups).
- Azure SQL uses full, differential, and transaction log backups in combination to enable PITR and other restore scenarios.
- Configure PITR retention and differential frequency on the server’s Backups page; enable LTR for long-term archival (up to 10 years).
- For SQL Server on Azure VMs, use the Recovery Services vault and select “SQL on Azure VM” to configure backups: https://learn.microsoft.com/azure/backup/backup-introduction-to-azure-backup.
- Deleted-database restores must target the original server/managed instance; geo-restore is available for region-level failures.
- Azure SQL automatic backups overview: https://learn.microsoft.com/azure/azure-sql/database/automatic-backups-overview
- Point-in-time restore (PITR): https://learn.microsoft.com/azure/azure-sql/database/point-in-time-restore
- Geo-restore overview: https://learn.microsoft.com/azure/azure-sql/database/geo-restore-overview
- Long-term retention (LTR): https://learn.microsoft.com/azure/azure-sql/database/long-term-retention-overview
- Azure Backup (Recovery Services vault): https://learn.microsoft.com/azure/backup/backup-introduction-to-azure-backup