Backup Solutions

RDS supports automated and manual backups. You can periodically back up databases. If a database is faulty or data is damaged, you can restore the database using backups to ensure data reliability.

RDS uses sysbench to import data models and a certain amount of data. After data is backed up, the compression ratio is about 80%. The more duplicate data there is, the higher the compression ratio is.

Compression ratio = Space occupied by backup files/Space occupied by data files x 100%

Backup Types

Full backup: A full backup is to back up all data, even if no data has changed since the last backup.
Full backups can be triggered automatically (by configuring an intra-region backup policy) or manually.
Incremental backup (binlog backup): RDS automatically backs up data modifications made after the most recent full or incremental backup every five minutes.

How RDS Backs Up Data

Single instance
A single-node architecture, which is more cost-effective than mainstream primary/standby DB instances. After a backup is triggered, data is backed up from the primary instance and stored as a package on OBS. The backup does not take up storage space of the instance.
Primary/standby instance
An HA architecture. In a primary/standby pair, each instance has the same instance class. After a backup is triggered, data is backed up from the standby instance and stored as a package on OBS. The backup does not take up storage space of the instance.

If a database or table in the primary instance is maliciously or mistakenly deleted, the database or table in the standby instance will also be deleted. In this case, you can only use backups to restore the deleted data.

Backup Solutions

Table 1 lists RDS backup solutions.

**Table 1** Backup solutions
Task	Backup Type	Description
Backing up data	Automated backups	RDS automatically creates full backups for your instance during a backup window you specified and saves the backups based on the configured retention period. If necessary, you can restore data to any point in time within the backup retention period. Once the automated backup policy is enabled, a full physical backup is triggered immediately. After that, full backups will be created according to the specified time window and backup cycle. Incremental backups are automatically created every 5 minutes to ensure data reliability.
	Manual backups	Manual backups are user-initiated full backups of instances. The backup method is physical backup. Manual backups will not be deleted until you delete them manually.
	Incremental backups	Incremental backups are binary log (binlog) backups. Binary logging is enabled for RDS for MariaDB instances by default. You do not need to set an interval for incremental backups because RDS automatically backs up incremental data every 5 minutes. Incremental backups can be used to restore data to a specific point in time.
Downloading backups	Downloading a Full Backup File	You can use OBS Browser+, the browser, or the download URL to download a full backup.
Downloading backups	Downloading incremental backups	You can download a single binlog file or merged binlog file. To download a merged binlog file, use any of the following methods: OBS Browser+, the browser, or the download URL.

Billing

Backups are saved as packages in OBS buckets. Backups occupy backup space in OBS. If the free space RDS provides is used up, the additional space required will be billed. For the billing details, see How Is RDS Backup Data Charged?

Deleting Backups

Manual backups and automated backups can be deleted in different ways:
- Manual backups can only be manually deleted.
- Automated backups cannot be manually deleted. You can adjust their retention period by referring to Configuring an Intra-Region Backup Policy, and backups that expire will be automatically deleted.
Local binlogs
If the retention period is set to 0, the binlogs of your DB instance will be deleted once they are synchronized to the standby instance and read replicas and successfully backed up to OBS.

If the retention period is set to a value greater than 0, for example, 1 day, the binlogs will be retained for one day after they are synchronized to the standby instance and read replicas from the primary instance and successfully backed up to OBS. After the retention period expires, the binlogs will be automatically deleted.