Copy-only backups
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's 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 can't serve as a differential base or differential backup and doesn't 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, doesn't 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 more information, follow the instructions in the article Example: Online restore of a read-write file (full recovery model), using the copy-only backup files instead.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 backups can't 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 can't be exported, so you couldn't 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.
Create a copy-only backup
You can create a copy-only backup with SQL Server Management Studio, Azure Data Studio, Transact-SQL, or PowerShell.
A. Use SQL Server Management Studio
In this example, a copy-only backup of the Sales database is 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 select Back Up....On the General page in the Source section, check the Copy-only backup checkbox.
Select OK.
B. Use 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. Use Transact-SQL and Azure SQL Managed Instance
Azure SQL Managed Instance supports taking COPY_ONLY full backups. The example performs a COPY_ONLY backup of MyDatabase to the Microsoft Azure Blob Storage. The storage Account name is mystorageaccount. The container is called myfirstcontainer. A storage access policy has been created with read, write, delete, and list rights. The SQL Server credential, https://mystorageaccount.blob.core.windows.net/myfirstcontainer, was created using a Shared Access Signature that is associated with the Storage Access Policy secret. For information on SQL Server backup to the Microsoft Azure Blob Storage, see SQL Server Backup and Restore with Microsoft Azure Blob Storage and SQL Server Backup to URL.
-- Prerequisite to have write permissions
CREATE CREDENTIAL [https://mystorageaccount.blob.core.windows.net/myfirstcontainer]
WITH IDENTITY = 'SHARED ACCESS SIGNATURE',
SECRET = 'sp=...' -- Enter your secret SAS token here.
BACKUP DATABASE MyDatabase
TO URL = 'https://mystorageaccount.blob.core.windows.net/myfirstcontainer/MyDatabaseBackup.bak'
WITH STATS = 5, COPY_ONLY;
To take a copy-only backup divided into multiple stripes, use this example:
BACKUP DATABASE MyDatabase
TO URL = 'https://mystorageaccount.blob.core.windows.net/myfirstcontainer/MyDatabase-01.bak',
URL = 'https://mystorageaccount.blob.core.windows.net/myfirstcontainer/MyDatabase-02.bak',
URL = 'https://mystorageaccount.blob.core.windows.net/myfirstcontainer/MyDatabase-03.bak',
URL = 'https://mystorageaccount.blob.core.windows.net/myfirstcontainer/MyDatabase-04.bak'
WITH COPY_ONLY;
D. Use 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