Copy-Only Backups

Article
02/28/2023
2 minutes to read

Applies to: SQL Server Azure SQL Managed Instance

A copy-only backup is a SQL Server backup that is independent of the sequence of conventional SQL Server backups. Usually, taking a backup changes the database and affects how later backups are restored. However, occasionally, it is useful to take a backup for a special purpose without affecting the overall backup and restore procedures for the database. Copy-only backups serve this purpose.

The types of copy-only backups are as follows:

Copy-only full backups (all recovery models)

A copy-only backup cannot serve as a differential base or differential backup and does not affect the differential base.

Restoring a copy-only full backup is the same as restoring any other full backup.
Copy-only log backups (full recovery model and bulk-logged recovery model only)

A copy-only log backup preserves the existing log archive point and, therefore, does not affect the sequencing of regular log backups. Copy-only log backups are typically unnecessary. Instead, you can create a new routine log backup (using WITH NORECOVERY) and use that backup together with any previous log backups that are required for the restore sequence. However, a copy-only log backup can sometimes be useful for performing an online restore. For an example of this, see Example: Online Restore of a Read-Write File (Full Recovery Model).

The transaction log is never truncated after a copy-only backup.

Copy-only backups are recorded in the is_copy_only column of the backupset table.

Important

In Azure SQL Managed Instance copy-only backup cannot be created for a database encrypted with service-managed Transparent Data Encryption (TDE). Service-managed TDE uses internal key for encryption of data, and that key cannot be exported, so you could not restore the backup anywhere else. Consider using customer-managed TDE instead to be able to create copy-only backups of encrypted databases, but make sure to have encryption key available for later restore.

To Create a Copy-Only Backup

You can create a copy-only backup by using SQL Server Management Studio, Transact-SQL, or PowerShell.

Examples

A. Using SQL Server Management Studio

In this example, a copy-only backup of the Sales database will be backed up to disk at the default backup location.

In Object Explorer, connect to an instance of the SQL Server Database Engine and then expand that instance.
Expand Databases, right-click Sales, point to Tasks, and then click Back Up....
On the General page in the Source section check the Copy-only backup checkbox.
Click OK.

B. Using Transact-SQL

This example creates a copy-only backup for the Sales database utilizing the COPY_ONLY parameter. A copy-only backup of the transaction log is taken as well.

BACKUP DATABASE Sales
TO DISK = 'E:\BAK\Sales_Copy.bak'
WITH COPY_ONLY;

BACKUP LOG Sales
TO DISK = 'E:\BAK\Sales_LogCopy.trn'
WITH COPY_ONLY;

Note

COPY_ONLY has no effect when specified with the DIFFERENTIAL option.

C. Using PowerShell

This example creates a copy-only backup for the Sales database utilizing the -CopyOnly parameter.

Backup-SqlDatabase -ServerInstance 'SalesServer' -Database 'Sales' -BackupFile 'E:\BAK\Sales_Copy.bak' -CopyOnly

Related Tasks

To create a full or log backup

To view copy-only backups

backupset (Transact-SQL)

To set up and use the SQL Server PowerShell provider

SQL Server PowerShell Provider