Automatically or manually back up an ApsaraDB RDS for SQL Server instance - ApsaraDB RDS

ApsaraDB RDS for SQL Server supports automatic backup and manual backup. You can specify a backup cycle in a backup policy to automatically back up your the data of your ApsaraDB RDS for SQL Server instance. You can also manually back up your RDS instance. If log backup is enabled for your RDS for SQL Server instance, you can restore the instance to any point in time within the backup retention period.

Backup description

Data backup

RDS for SQL Server supports two data backup methods: physical backup and snapshot backup. For more information, see Use the snapshot backup feature.

Backup method	Feature
Physical backup	Full physical backups and incremental physical backups are supported. Logical backups are not supported. By default, the incremental backup feature is enabled to reduce the size of backup files. Automatic backups are performed based on the backup cycle of a full backup following incremental backups. Click to view the incremental backup policy After a full backup is successfully performed, the system automatically performs an incremental backup within three days starting from the day on which the full backup is performed. The system automatically performs a full backup three days after the previous full backup. Before an incremental backup is performed, the system automatically checks whether new databases are created after the previous full backup. If one or more databases are created after the previous full backup, a full backup instead of the incremental backup is performed to ensure data in the new databases is also backed up. If data may be damaged, the system automatically performs a full backup. For example, data may be damaged due to database creation failures or previous data backup failures. If you perform a full backup during a backup cycle, the system automatically performs an incremental backup within three days starting from the day on which the full backup is performed. Note If the backup frequency is once a day, the system performs a full backup on the first day of a backup cycle and performs two consecutive incremental backups within the remaining two days following the full backup. If the incremental backup feature is disabled, no incremental backups are performed. Instead, full backups are performed within the backup cycle. Backups for individual databases are supported. You can back up one or more databases of your RDS instance. The system shrinks the transaction logs of the RDS instance during each backup. You can log on to the ApsaraDB RDS console and go to the Backup and Restoration page of your RDS instance. Then, click Shrink Transaction Log to manually shrink transaction logs. By default, backups are performed on the primary RDS instance. If your RDS instance runs RDS Cluster Edition, you can configure settings to allow physical backups to be preferentially performed on the secondary RDS instance. This reduces the I/O loads of the primary RDS instance and improves instance performance and stability. Expand to view the usage notes of the secondary database backup feature The default physical backup mode for a new RDS instance that runs RDS Cluster Edition is primary database only. If you click Switch to Advanced Backup Policy to configure backup policies for an RDS instance that runs RDS Cluster Edition, you cannot specify a backup priority. The secondary database backup feature does not support incremental backups. If you use this feature, the system performs full backups instead of incremental backups. This increases the amount of backup data. To prevent an excessively large amount of backup data, we recommend that you modify the backup policy. For example, you can change the backup policy from one backup every day to one backup every two days. If you use the secondary database preferred mode for your RDS instance that runs RDS Cluster Edition, backups are preferentially performed on the secondary RDS instance. If the secondary RDS instance does not meet the backup conditions, backups are automatically performed on the primary RDS instance. For example, if the secondary RDS instance is unavailable, backups are automatically performed on the primary RDS instance. If you change the backup policy to secondary database backup and modify the backup time, a full backup may be triggered 2 minutes later. In this case, if the secondary RDS instance does not meet the backup conditions, backups are automatically performed on the primary RDS instance. This affects your workloads. For example, if the secondary RDS instance is unavailable, backups are automatically performed on the primary RDS instance. To reduce the impact of resource consumption caused by backup operations on instance performance, we recommend that you modify the backup policy and backup time during off-peak hours. Transaction log shrinking is forcefully performed on the primary RDS instance, and cannot be performed on the secondary RDS instance. If the RDS instance uses the secondary database backup policy and you manually shrink the transaction logs of the instance, transaction log shrinking is forcefully scheduled to the primary RDS instance.
Snapshot backup	Full snapshot backups are periodically performed based on the backup cycle that you specify. Compared with physical backup, the snapshot backup method is faster and has minimal impact on instance performance.

Log backup

The system automatically generates log backup files for your RDS instance based on the backup frequency that you specify. The following backup frequencies are supported: Same as Data Backup, Every 5 Minutes, and Every 30 Minutes.
Note
- The total size of log backup files does not vary with the backup frequency.
- After you change the backup method to Snapshot Backup, the backup frequency can be set only to Every 5 Minutes or Every 30 Minutes.
The log backup feature is enabled by default and cannot be disabled. You can specify a log backup retention period that ranges from 7 days to 730 days.
You can download log backup files.
Note
If the backup frequency is set to Every 30 Minutes or Every 5 Minutes, you can restore the data of your RDS instance that runs RDS Basic Edition to a specific point in time within the previous 30 minutes or 5 minutes in the event of cloud disk damage or other unexpected failures.

Prerequisites

The AliyunServiceRoleForDBS service-linked role is created by using your Alibaba Cloud account if you use the backup feature of ApsaraDB RDS for the first time.

Usage notes

After you modify the backup time of your RDS instance, a backup may be triggered 2 minutes later. This may cause high I/O bandwidth on the primary RDS instance and affect your workloads. We recommend that you modify the backup time during off-peak hours to minimize the impact of resource consumption caused by backup operations on the performance of your RDS instance.
When you perform a physical backup on your RDS instance, the backup speed is fast and cannot be limited. This may cause high I/O bandwidth and affect your workloads. To minimize the impact on the performance of your RDS instance, we recommend that you perform physical backups during off-peak hours.
If your RDS instance has a large amount of data, a backup may require a long period of time.
You cannot back up or restore cold storage databases.This applies if you enable the feature to archive data to an Object Storage Service (OSS) bucket and the required database is converted into a cold storage database.
Backup files are retained for a specific period of time. Before the retention period elapses, we recommend that you download the backup files that need to be retained for a long period of time to your computer. This prevents data loss due to expiration.
The RDS instance collects traffic statistics from the network interface controllers to reflect the bandwidth usage in SQL Server. Statistics about the traffic that is consumed by data backups are also collected. The amount of traffic on your RDS instance surges during a data backup.

Billing rules

Each RDS instance is allocated a free quota for backup storage. If the backup storage of your RDS instance does not exceed the free quota, you are not charged for backup storage. If the backup storage exceeds the free quota, you are charged for the excess storage that you use. For more information about the free quota and billing rules, see Backup storage fees.

Configure automatic backups

After you configure a backup policy for your RDS instance, the system automatically and periodically backs up the RDS instance based on the backup policy. In some regions, you can use the spare backup feature by enabling the advanced backup settings on the Backup Strategy tab. If you cannot find the entry point to enable the advanced backup settings on the Backup Strategy tab, submit an application. For more information, see Switch to the advanced backup settings and Use the spare backup feature. After you enable the advanced backup settings, the entry point to configure backup policies and the method to configure some parameters are changed. You must configure the backup policies and parameters based on your business requirements.

Regular backup (before the upgrade)

Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.
In the left-side navigation pane, click Backup and Restoration.
On the Backup Strategy tab of the Backup and Restoration page, click Edit in the Data Backup Settings section.

In the dialog box that appears, configure the following parameters and click Save.

Parameter	Description
Data Backup Retention (Days)	The data backup retention period. Valid values: 7 to 730. Default value: 7. Unit: days.
Backup Cycle	The cycle based on which you want to perform a backup. You must select at least two days of the week.
Backup Method	The backup method that you want to use. Valid values: Snapshot Backup: The system backs up the data from cloud disks at a specific point in time. The backup speed is fast. Physical Backup: This is the default backup method. The system creates a replica of the data of your RDS instance. The backup speed is slow. Important After you change the backup method to Snapshot Backup, you can still perform a Physical Backup when you manually back up your RDS instance. For more information, see Back up an ApsaraDB RDS for SQL Server instance.
Backup Priority	The backup priority of the backup method that you select. This parameter is available only if your RDS instance runs RDS Cluster Edition and uses the Physical Backup. Valid values: Primary Instance Only: Backups are performed only on the primary RDS instance. Secondary Instance Preferred: Backups are performed on the secondary RDS instance. This helps reduce the I/O loads of the primary RDS instance and improve instance performance and stability. If the secondary RDS instance does not meet the backup conditions, backups are automatically performed on the primary RDS instance. For example, if the secondary RDS instance is unavailable, backups are automatically performed on the primary RDS instance. Note This parameter is available only if your RDS instance runs RDS Cluster Edition. If you set this parameter to Secondary Instance Preferred, incremental backup and 5-minute log backup are not supported.
Incremental backup	Specifies whether to enable the incremental backup feature. Note If you set the Backup Method parameter to Snapshot Backup or your RDS instance runs RDS Cluster Edition and uses the Physical Backup method, you cannot enable the incremental backup feature.
Backup Time	The period of time during which a data backup operation is performed. For example, you can set this parameter to 06:00-07:00. We recommend that you select an off-peak hour.
Backup Frequency	The frequency to generate log backup files. Valid values: Same as Data Backup, Every 5 Minutes, and Every 30 Minutes. Important The log backup retention period is the same as the data backup retention period. You cannot separately configure the log backup retention period. If you set the Backup Priority parameter to Secondary Instance Preferred, 5-minute log backup is not supported.

Sparse backup (after the upgrade)

Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.
In the left-side navigation pane, click Backup and Restoration.
On the Backup and Restoration page, click the Backup Strategy tab. On the tab that appears, move the pointer over the circled number between SQL Server and Level-1 Backup to view the backup policies that you configured.

Configure the following parameters and click OK.

Parameter	Description
Backup Policy	The time range within which the backup is performed and the retention period of the backup sets. The backup must be performed at least twice a week. Note You can click Add Backup Policy to configure the sparse backup feature. This way, you can configure backup policies in a more flexible manner and retain the minimum number of backup sets.
Backup Time	The period of time during which a backup operation is performed. For example, you can set this parameter to 07:00-08:00. We recommend that you select an off-peak hour.
Incremental Backup	Specifies whether to enable the incremental backup feature. Note If you set the Backup Method parameter to Snapshot Backup, you cannot enable the incremental backup feature.
Backup Method	The backup method that you want to use. Valid values: Snapshot Backup: The system backs up the data from cloud disks at a specific point in time. The backup speed is fast. Physical Backup: This is the default backup method. The system creates a replica of the data of your RDS instance. The backup speed is slow. Important After you change the backup method to Snapshot Backup, you can still perform a Physical Backup when you manually back up your RDS instance. For more information, see Back up an ApsaraDB RDS for SQL Server instance.
Backup Frequency	The frequency to generate log backup files. Valid values: Same as Data Backup and Every 30 Minutes. Note The log backup retention period is the same as the data backup retention period. You cannot separately configure the log backup retention period.
Log Backup Retention Period	The log backup retention period. The log backup retention period must be less than or equal to the data backup retention period. Valid values: 7 to 7300. Unit: days. Default value: 7.

On the Backup Strategy tab, click Save in the lower-left corner.

Configure manual backups

Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.
In the upper-right corner of the page, click Backup Instance.Backup Instance

Configure the following parameters and click OK.

Parameter	Description
Backup Policy	Snapshot Backup: The system backs up the data from cloud disks at a specific point in time. The backup speed is fast. Physical Backup: This is the default backup method. The system creates a replica of the data of your RDS instance. The backup speed is slow. Note The Snapshot Backup option is displayed only when the automatic backup policy is set to Snapshot Backup.
Select Backup Mode	Full Backup: The system immediately performs a full backup. Automatic Backup: If no full backup has been performed for the instance within the latest three days, the system immediately performs a full backup. Otherwise, the system immediately performs a differential backup. Note If the RDS instance runs RDS Cluster Edition, the automatic backup policy is set to Physical Backup, and Secondary Database Preferred is selected, only Full Backup is supported.
Backup Policy	This parameter is available only when the Select Backup Mode parameter is set to Full Backup. Instance Backup: The system backs up all data of your RDS instance. Single-Database Backup: The system backs up only the databases that you specify. This parameter is available only if the Backup Policy parameter is set to Physical Backup. Note If you select Single-Database Backup, the Database section appears. In this section, select the databases that you want to back up from the left-side list and click the > icon to move the selected databases to the right-side list. If no databases are created on your RDS instance, you must create databases before you back up your RDS instance. For more information, see Create a database on an ApsaraDB RDS for SQL Server instance.

After you configure a backup policy, a backup task is created. You can click the icon in the upper-right corner of the page. On the Tasks page, set the Task Type parameter to Manual Backup and view the progress of the backup task.
Note
After the backup task is complete, you can download the backup file on the Data Backup or Log Backup tab on the Base Backups tab of the Backup and Restoration page.

References

You can download existing data backup files or log backup files to your on-premises device for archiving.
You can use data backups and log backups to restore data to an existing RDS instance, a new RDS instance, or a self-managed SQL Server instance. For more information, see Methods to restore an ApsaraDB RDS for SQL Server instance.
The default backup feature that is provided by the system stores backup files in the same region as your RDS instance. For more information about how to store backup files in a region that is different from the region of your RDS instance, see Use the cross-region backup feature.
You can also call the following API operations to manage the backup policy of an RDS instance:

FAQs

Can I disable the data backup feature or the log backup feature for my RDS instance?

No, you cannot disable the features. By default, the data backup and log backup features are enabled and cannot be disabled. You can reduce the backup frequency, such as twice a week.

Note

The log backup retention period is the same as the data backup retention period. You cannot separately configure the log backup retention period.

How do I delete or reduce the number of data backup and log backup files?

Data backup and log backup files cannot be manually deleted. If the size of your backup files exceeds the free quota, you can use the following methods:

Reduce the total size of backup files.
Backup files cannot be manully deleted. However, you can reduce the backup frequency to reduce the number of backup files. You can also shorten the backup retention period, which allows the system to automatically delete expired backup files. For more information, see Back up an ApsaraDB RDS for SQL Server instance.
Increase the free quota.
The free quota varies based on the storage capacity of your RDS instance. For example, your RDS instance uses the physical backup method and is expanded from 150 GB to 300 GB, the free quota increases from 75 GB to 150 GB. For more information, see Change instance specifications.

Why are incremental backups not supported by the snapshot backup feature?

Snapshot backups are used to periodically back up data snapshots on cloud disks. You can use the snapshots to quickly restore data to a specific point in time. Snapshots are created based on cloud disks instead of backup files. As a result, the snapshot backup feature does not support incremental backups.

Note

Snapshots use the incremental snapshot chain mechanism. This mechanism retains the status of a snapshot at each point in time. As a result, a snapshot backup only backs up the incremental and updated data on cloud disks.

Why are incremental backups not supported by the secondary database preferred mode?

The differential bitmaps cannot be deleted from the secondary RDS instance due to kernel reasons of ApsaraDB RDS for SQL Server. As a result, the secondary database preferred mode does not support incremental backups. For more information, see official documentation.

If the incremental backup feature is enabled, is the existing automatic backup policy affected after I manually perform a full backup?

If the incremental backup feature is enabled and you perform a full backup during a backup cycle, the system automatically performs an incremental backup within three days starting from the day on which the full backup is performed. For example, a full backup is performed on Monday and an incremental backup is performed on Tuesday. If a full backup is performed on Wednesday, an incremental backup is separately performed on Thursday and Friday.

What are the differences between the snapshot backup and the physical backup features?

Item	Physical backup	Snapshot backup
Log backup frequency	The following backup frequencies are supported: Same as Data Backup Every 30 Minutes Every 5 Minutes	The following backup frequencies are supported: Every 30 Minutes Every 5 Minutes
Restoration speed	The restoration is fast. The restoration speed varies based on the specifications of your RDS instance.	The restoration is extremely fast. The restoration speed is not affected by the amount of data. The speed of restoring data from a snapshot backup is higher than the speed of restoring data from a physical backup. Expand to view the estimated restoration time Restore data to a new RDS instance The time that is required to restore data from a backup set is approximately 30 minutes. This includes the time that is required to create an RDS instance and the time that is required to restore the data from the backup set. The time that is required to restore data to a point in time varies based on the log backup file that is used. This includes the time that is required to create an RDS instance and the time that is required to restore the data from the log backup file. Restore data to an existing RDS instance The time that is required to restore data from a backup set is approximately 10 minutes. The time that is required to restore data to a point in time varies based on the log backup file that is used. Note The log backup files that are used are generated between the point in time at which the most recent snapshot backup file is generated and the point in time to which you want to restore data.
Amount of data supported	Unlimited.	Unlimited.
Impact on instance performance	A large number of resources are consumed. This significantly affects the performance of your RDS instance. We recommend that you perform a physical backup during off-peak hours.	Only a small number of I/O resources are consumed. This does not significantly affect the performance of your RDS instance. You can perform a snapshot backup at any time.
Backup file download	Physical backup files can be downloaded.	Snapshot backup files cannot be downloaded.