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 include automated backups and manual backups.
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.

Figure 1 How RDS backs up data (CBR disabled)

Backup Solutions

Table 1 describes how to back up data and download backups.

**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. You can contact customer service to enable CBR. After CBR is enabled, a full scan will be performed for the first snapshot backup within seven days. The required time depends on how much data there is in your instance. Incremental scans will be performed for subsequent backups within seven days, greatly shortening the backup duration.
	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. You can contact customer service to enable CBR. After CBR is enabled, a full scan will be performed for the first snapshot backup within seven days. The required time depends on how much data there is in your instance. Incremental scans will be performed for subsequent backups within seven days, greatly shortening the backup duration.
	Incremental backups	Incremental backups are binary log (binlog) backups. Binary logging is enabled for RDS for MySQL instances by default. RDS automatically backs up data modifications made after the most recent automated or incremental backup every five minutes.
	Backup using mysqldump	You can use the backup tool provided by the MySQL client to back up data for your instance.
Backing up data across regions	Cross-region backups	RDS can store backups in a different region from the DB instance for disaster recovery. If a DB instance in one region fails, you can use backups from another region to restore the data to a new DB instance.
Downloading backups	Downloading full backups	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 details, see How Is RDS Backup Data Billed?

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. To delete them, you can adjust the retention period specified in your automated backup policy. When the retention period expires, automated backups will be 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.